At the heart of the row between the now former work and pensions secretary Iain Duncan Smith and his government are PIPs - Personal Independence Payments.

But why have they become so controversial?
PIPs are benefit payments made to help people aged 16 to 64 cope with the extra costs they face due to ill health or disability. Not means-tested, they are gradually replacing Disability Living Allowance (DLA).
Nearly 700,000 people currently claim PIP, with another 1.5 million still to be reassessed.
DLA was commonly based on self-assessment, whereas eligibility for PIP includes a test carried out by Atos or Capita on behalf of the government. Money is allocated according to a points system and eligibility is kept under regular review.
The criteria for PIP were already stricter than DLA - for example, in the past someone was considered to be "virtually unable to walk", and therefore eligible, if they could not walk more than about 50 metres. Under PIP, that was dropped to 20 metres, excluding, at the government's estimate, more than 420,000 people.
Ministers wanted to make the criteria stricter still and that desire is at the crux of the current row.
There are two components - daily living and mobility - and eligibility is based on ability to carry out 12 activities, including eating and drinking, washing, going to the toilet, communicating and getting around.
The more severe someone's needs the more they will receive - up to a maximum of £139.75 a week.
The money can be spent on a wide range of things. The mobility element often goes towards specially adapted cars, scooters or wheelchairs, paid for via the Motability scheme. The daily living element can cover anything from a prosthesis to specially designed utensils, hand rails and toilet seats.
The plan was to reduce the weighting given to two of the 10 criteria for the daily living element - dressing and managing toilet needs. So, instead of someone who needs grab rails to use the toilet receiving two points, they would have only received one.
That single point difference could have meant an individual getting less money, or losing PIP altogether if it put them below the points threshold for qualifying.
An independent review carried out for the Department for Work and Pensions found that "a significant number of people are likely to be getting the benefit despite having minimal to no ongoing daily living extra costs".
The department says it reviewed a "number of cases" and in 96% of them the "likely ongoing extra costs of daily living were nil, low or minimal" - for example, because many of the aids and appliances which people are currently getting points for are provided free by the NHS and councils, or could be bought cheaply.
Number 10 also says the cost of PIPs is rising by around a billion pounds a year and needs to be brought under control.
Yes. In his first Budget in 2010, George Osborne made reforming DLA a priority.
Four years later, in October 2014, the Office for Budget Responsibility (OBR) forecast that spending on disability benefits between 2015 and 2019 would total £55.9bn. By March 2016, that figure had risen to £66.4bn.
The switch to PIP was designed to save money - something sources close to Mr Duncan Smith are continuing to insist it will ultimately do - but things are not as simple as that.
Those same sources have told the BBC the problems are "to do with people transferring to PIP from DLA. They are sicker than the DLA system said they were."
The OBR said the rising costs were because of higher-than-expected caseloads - and people getting more money than ministers had predicted. The average payout is now £100 a week, 14% higher than expected.
Costs have also risen because claimants are being increasingly successful in appealing against officials' decisions, often helped by charities.
Not everyone would have lost out, and those who did would have only lost cash as and when their conditions were reassessed.
However, charities said up to 640,000 people would be affected by 2020, each standing to lose up to £100 a week.
Labour said the changes would have removed the ability of many people to live independently.
And of course, the loudest critic of all has been Mr Duncan Smith, who said the decision to "juxtapose" the changes with tax cuts for the better off in the Budget was the final straw.
For its part, the government says making the criteria stricter would have saved £1.2bn a year and made the system "fairer". More broadly, it puts the changes in the context of the planned introduction of Universal Credit - the new single monthly payment of benefits and tax credits due for roll-out from 2017 - under which it says some people will be better off.
The proposals have been shelved.
However, the government said just a few days before the Budget that it wanted to save a further £4.4bn from the UK welfare bill. Asked how the chancellor would cover the shortfall created by not going ahead with the PIP changes, Downing Street suggested the issue would be looked at in the Autumn Statement.
Number 10 has, though, stressed that PIP will still have to be reformed in the future as the cost is "unsustainable."
More broadly, there is the political fall-out. What damage has been done to George Osborne and indeed, David Cameron, and the impact Mr Duncan Smith's resignation will have on the EU referendum campaign, all remain to be seen.


Tottenham's Harry Kane is one of four players to make the shortlist for both the Professional Footballers' Association Player and Young Player of the Year prize.

Manchester United keeper David De Gea, Chelsea forward Eden Hazard and Liverpool attacking midfielder Philippe Coutinho could also win both awards.
Arsenal's Alexis Sanchez and Chelsea's Diego Costa complete the senior list.
Manchester City's Lucy Bronze, winner in 2014, is on the women's shortlist.
It is the first time four players have been nominated for both the Player and Young Player awards.
Hazard makes the senior shortlist for the third successive year, having previously lost out to Gareth Bale and Luis Suarez.
Bale's triumph in 2013 meant he emulated Andy Gray in 1977 and 2007 winner Cristiano Ronaldo by winning both prizes.
De Gea is aiming to become the first goalkeeper to win the award since Peter Shilton in 1977.
Liverpool's Raheem Sterling and Chelsea goalkeeper Thibaut Courtois have been nominated for the Young Player prize.
Chelsea Ladies are the only Women's Super League side to have two players nominated in Eniola Aluko and South Korea international Ji So-yun. Birmingham's Karen Carney, Arsenal's Kelly Smith and Notts County's Jess Clarke are also named.
Leah Williamson, who kept her nerve in unique circumstances to score the penalty that sent England into the European Under-19 Championship, is included in a five-person shortlist for the Young Player award.
No-one from WSL champions Liverpool has been nominated.
Diego Costa (Chelsea)
David De Gea (Manchester United)
Philippe Coutinho (Liverpool)
Eden Hazard (Chelsea)
Harry Kane (Tottenham Hotspur)
Alexis Sanchez (Arsenal)
Thibaut Courtois (Chelsea)
Philippe Coutinho (Liverpool)
David De Gea (Manchester United)
Eden Hazard (Chelsea)
Harry Kane (Tottenham Hotspur)
Raheem Sterling (Liverpool)
Eniola Aluko (Chelsea)
Lucy Bronze (Manchester City)
Jess Clarke (Notts County)
Karen Carney (Birmingham City)
Kelly Smith (Arsenal)
Ji So-yun (Chelsea)
Freda Ayisi (Birmingham City)
Hannah Blundell (Chelsea)
Aoife Mannion (Birmingham City)
Nikita Parris (Manchester City)
Amy Turner (Notts County)
Leah Williamson (Arsenal)


Swansea City are weighing up a move to re-sign striker Wilfried Bony from Manchester City.

The Ivorian left the Swans for the Etihad Stadium on a four-year contract in 2015 for a fee worth up to £28m.
Bony, 28, managed only eight goals in 46 appearances for City - more than half of which came as a substitute - and spent last season on loan at Stoke.
His potential return to Wales could depend on the future of Swansea's top scorer last season, Fernando Llorente.
The 32-year-old, who is currently sidelined with an arm injury, has been a transfer target for Chelsea, having worked with the Premier League champions' manager, Antonio Conte, at Juventus.
Swansea have yet to receive a bid this summer for the Spain international, who scored 15 goals last season to help the Welsh club avoid relegation from the top flight.
The Swans did reject offers for Llorente during the January transfer window, and a move for Bony could be seen as insurance should Llorente leave.
Swansea signed England Under-21 striker Tammy Abraham on a season-long loan from Chelsea earlier this summer.
But with club record signing Borja Baston on loan at Malaga, the Swans could be short of forward options if Llorente was to leave.
Before Baston's arrival, Bony was Swansea's record signing when he joined from Vitesse Arnhem for £12m in 2013.
He scored 34 goals in all competitions for the Swans before his move to City.
Bony's high wages at City were thought to be a stumbling block for a potential return to the Liberty Stadium, though Swansea could soon have more money if midfielder Gylfi Sigurdsson joins Everton.


Dundee United boss Ray McKinnon insists his side paid the price for their hectic play-off schedule in Sunday's defeat to Hamilton Accies.

A 1-0 second-leg win ensured Accies retained their top-flight status.
United had to come through two two-legged ties to reach the final, at which point Hamilton, 11th in the Premiership, entered the play-offs.
"The six games has taken its toll - it was an evenly contested game but I felt we ran out of steam," McKinnon said.
"I'm not making that an excuse, it's just a fact. You could see the legs were gone in the second half. We didn't have the same intensity to our play or our pressing."
McKinnon's side, who finished third in the Championship, overcame Morton 5-1 on aggregate in the play-off quarter-final and beat Falkirk 4-3 on aggregate in the semi-final.
But following a 0-0 draw with Hamilton at Tannadice in the final first-leg, Greg Docherty's goal on Sunday was enough to consign United to a first defeat in 12 games and at least another season in the second tier.
"We were running on empty and I'm really disappointed for the players because they wanted it so much," McKinnon added.
"We came down here with high hopes considering the form we're in, but unfortunately we've just come up short at the final hurdle.
"We've been using the same players regularly over the last six to 10 weeks and that's taken its toll today. They've given everything, they tried everything to get back into the game but just didn't have the legs at the end."
McKinnon said the staff and players were left "feeling flat" by the result but he is already hopeful that his side will be better equipped for another promotion push next season.
"We have to work hard over the close season to identify people we can attract to the club, better quality than what we've got - we need to improve that," he said.
"We're going to work hard to put a really good squad together. We've started the recruitment process well with James Keatings and Billy King (already signed). If we can maintain that kind of standard, we'll give ourselves a great chance next season."


A man who murdered his six-year-old daughter was described as displaying a "pattern of impulsive violence" months before she died, it has been revealed.

Ellie Butler was killed by Ben Butler at their Sutton home in 2013, 11 months after she was returned to his care.
A pre-sentence report about Butler in July 2013 - three months before he killed his daughter - said he posed a "medium risk of serious harm".
It was revealed after a secret family court ruling from 2014 was made public.
The 36-year-old was sentenced to life with a minimum of 23 years at the Old Bailey in June.
Family court proceedings were heard by Mrs Justice Eleanor King after Ellie had died, but before the murder trial, to decide the future care of her younger sibling who cannot be named for legal reasons.
In her judgement, the judge described a pre-sentence report which concluded Butler was "medium risk of serious harm to members of the public and staff, specifically when he is under personal stress".
The report was prepared when Butler appeared at Bromley Magistrates' Court for dishonestly claiming housing benefit for over two years.
It added: "There is clearly a pattern of impulsive violence committed. whether within the context of impulsive actions or when in conflict with others."
A spokesman for Sutton Council, which was involved in the care of the children while Ellie was alive, said there was "no evidence of any agency sharing with us the pre-sentence report of July 2013".
The family court judgement, which was released following a ruling by the Court of Appeal, also revealed that Ellie's younger sibling had suffered injuries at the hands of Butler.
"The father was, in my judgment, both routinely violent to the children and the children were regularly in his sole care," Mrs Justice King said.
On Thursday, a coroner said it was her "preliminary view" some of the agencies involved in Ellie's care should be investigated.
Butler has lodged an appeal against his conviction and sentence.
Ellie's mother Jennie Gray was convicted of child cruelty and perverting the course of justice and sentenced to 42 months in prison.


The Queen's horse Dartmouth won the Yorkshire Cup on the final day of the Dante Festival at York, as trainer Hughie Morrison was inadvertently caught up in more controversy.

Dartmouth, trained by Sir Michael Stoute, beat Simple Verse by a neck.
Morrison was later called before a stewards' inquiry after an employee of his was alleged to have urinated in the stable of his horse Marmelo.
The employee was subsequently found guilty of improper conduct.
Morrison was instructed by the British Horseracing Authority (BHA) to "ensure all of his employees are correctly briefed as to the integrity implications of these actions in the future".
He said: "There's nothing to it really. The lad is a long-standing employee. He knows he's made a mistake and he won't do it again."
Marmelo, who was fifth in the Yorkshire Cup, was ordered to have a routine doping test.
Urinating in a racecourse stable is banned because of the risk of cross contamination.
BBC horse racing correspondent Cornelius Lysaght said: "The chances of cross contamination are probably rather higher than 100-1, but of course it's possible, and this is an example, the BHA will say, of how all regulations relating to security and integrity on the racecourse are tightly enforced."
On Thursday, Morrison offered a reward of £10,000 to clear his name after one of his horses tested positive for an anabolic steroid.
Our Little Sister tested positive for nandrolone after finishing last in a race at Wolverhampton on 14 January, which had prize money of £2,500.
Dartmouth, the 11-4 favourite, was one of five horses in the running over the final furlong of Friday's race.
Having made his challenge on the stands-side rail, he snatched the verdict from Ralph Beckett's 2015 St Leger winner Simple Verse (13-2).
The pace-setting High Jinx, having his first race for 747 days, kept on in gritty fashion and was just a neck away to claim third on his first start for Yorkshire trainer Tim Easterby.
Winning rider Ryan Moore said: "He felt very easy the whole way, he's got mile-and-a-half pace, he was just doing a little too much in stages.
"He travelled beautifully and is such an honest horse, but it didn't help that I was apart from them and he's done very well."
BBC horse racing correspondent Cornelius Lysaght:
You don't have to be an arch-Royalist to enjoy the spectacle of the Queen beaming at a success for one of her runners at Royal Ascot.
And, after this narrow defeat of his nearest three rivals, Dartmouth - named after the Devon naval town - goes to the famous fixture in June with the wind in his sails.
It would be nice to think Dartmouth might try to emulate his owner's horse Estimate, who won Ascot's marathon Gold Cup four years ago, but he'll be sticking to the shorter Hardwicke Stakes this time.


A man has appeared in court charged with shooting dead a notorious gangland figure in West Lothian.

James Farrelly, 52, denies murdering Martin Hamilton, 53, in Mossside Drive, Blackburn, between 16 April and 17 December 2015.
It is alleged that, while acting with others, Mr Farrelly shot Hamilton in the head and inflicted blunt and sharp force injuries to his head.
He is also charged with hiding the body in woodland near the B7015.
It is also alleged that he removed kitchen units, appliances and flooring from the house in Mosside Drive, and cleaned and attempted to remove blood-staining from the house and from a van.
Farrelly, who is represented by Derek Ogg QC, is also accused of being concerned in the supply of cocaine and heroin between January 2001 and February 2016.
He denies all the charges against him and trial has been set for May.
Prosecutor Alex Prentice QC said: "The Crown position is that this is a fairly complicated case."
Hamilton, from Glasgow, was previously one of Scotland's most wanted men and was nicknamed the Blackhill Butcher, after the housing estate from which he operated..
He was released from prison in September 2014 but went missing in April last year.
He had been on the police's most-wanted list before he was jailed in 2000 over a string of charges including drug dealing, torture, abduction and sodomy.
The trial is expected to last between four and five weeks.


Brides in Birmingham say they've been left without their wedding dresses after a boutique closed without warning or explanation.

Emily Eve Bridal Boutique in the city centre closed unexpectedly, leaving dozens of women without a dress or a refund for their wedding day.
One bride said she'd spent over Â£1,000 on a deposit that she may not get back.
The boutique's website has been deleted and the BBC has been unable to contact its owners.
See more stories from Birmingham and the Black Country here
Lauren Davies said she spent Â£1,080 on a deposit for her dress ahead of her wedding next year. She said she has "absolutely no idea" how she's going to get the money back because she can't reach anyone at the company.
"I was apprehensive about sending that much money," she said. "Luckily I only paid the deposit."
"They took my money in April but my dress was never even ordered. My dress has now been discontinued so I don't think I'll be able to get my dress now."
Olivea Allegrini-Jones, who is getting married on Saturday, said: "I bought a dress last April. It got to July and I still hadn't heard anything."
When she received no response from the boutique last month, she went to the shop on Smallbrook Queensway and demanded a refund which she was able to get before the shop was left empty.
In a cached version of the website, the shop is listed as part of the Retail Bridalwear Association (RBA), and claims to be "a business that is financially sound, offering professional standards of care and service".
RBA has been approached for comment.


Great Britain's men won European Games gold in the team fencing foil with a 45-41 win over Olympic champions Italy.

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GB lost only three of the nine bouts, with Richard Kruse winning three, alongside team-mates Alex Tofalides and Marcus Mepstead.
There were six swimming medals, among them gold for Duncan Scott on the last day in the pool, but Natalie Powell and Gemma Gibbons missed out in the judo.
GB will finish with 47 medals in Baku; 18 gold, 10 silver and 19 bronze.
Kruse, who won the last bout against third-ranked Italy, said: "I knew we were capable of it.
"On paper they are the stronger team but we showed some real willpower today to come together and showed the whole is greater than the sum of its parts."
In judo, Welsh fighter Powell lost her bronze medal -78kg meeting with Ana Velensek of Slovenia and finished fifth.
The 24-year-old Commonwealth champion had earned a spot in the third-place bout after winning her repechage against Hungary's Abigel Joo.
Earlier on, Olympic silver medallist Gibbons was beaten in the round of 16 in the same weight category by Ukraine's Victoria Turks.
Speaking after her second-round defeat in Baku, Londoner Gibbons, 28, told BBC Sport: "It was a fight I needed to be winning.
"At the moment I'm managing to take some good wins but I'm not able to put three or four of them together. That's what it takes to win a tournament like this. It's not good enough.
"It's a tough tournament here - probably just under the level of a World Championships or Olympics. It's not an easy event but it's one we [Team GB] should be winning a couple of medals in."
Duncan Scott and Cameron Kurle secured a one-two in the 200m freestyle as Britain won six medals on the final day of swimming action.
Charlie Attwood picked up bronze in the 100m breaststroke while Abbie Wood was the day's other individual winner with bronze in her 200m individual medley final.
And there was more relay success for the Brits as the women's 4x200m freestyle team (Hannah Featherstone, Darcy Deakin, Georgia Coates and Holly Hibbott) took bronze and the men's 4x100m medley quartet (Scott, Attwood, Luke Greenbank and Martyn Walton) won silver to take the tally to 23 for the competition.


Welsh rally driver Elfyn Evans will return to the World Rally Championship (WRC) in 2017 after a 12-month absence.

Alongside co-driver Daniel Barritt, Evans will contest the entire WRC season as part of DMACK World Rally, but will drive the M-Sport Ford Fiesta.
His team-mates include the newly-crowned world champion, Sebastien Ogier and Estonian Ott Tanak.
The 28-year-old drove for M-Sport in the top class in 2014 and 2015, but was demoted to the WRC2 class in 2016.
"I am really excited, that was the goal last year to make it back in the top class," Evans told BBC Wales Sport.
"Last season in WRC2 made me more determined to make it back in to WRC.
"It is an open book this season with the brand new cars and new regulations, but I am aiming for the top positions. We want to get podiums and wins too."


Nintendo has bounced back into profit, thanks to a weaker Japanese yen.

The games maker reported an annual profit of 7.1bn yen ($72m; Â£47m), It suffered a loss of 43bn yen in the previous year.
But the company's sales dipped 1.9%, struggling against its rivals Sony and Microsoft, as the three battle it out in the $44bn games market.
Nintendo is behind PokÃ©mon and Super Mario, one of the most successful ever game franchises.
The major players are also facing challenges from firms that make cheap downloadable games for smartphones and tablets
The Japanese yen has been trading at around 95 yen to the dollar in recent months, compared to around 80 a year ago.
A weak yen makes products cheaper to buyers outside Japan.
Sales of Nintendo's Wii U consoles came in at 3.45 million units, well short of the four million annual target.
The Wii U, which went on sale late last year, was the first major new game console to arrive in stores in several years.
The company said a lack of game software had caused console sales to miss the targets.
Sony is promising to launch the latest version of its Playstation console later this year and Microsoft could also be set to release an updated Xbox by the busy festive season.


A bid to get homeless people in Wales off the streets has been launched.

The StreetLink scheme allows anyone to call or send an online alert about the location of someone they see sleeping rough.
Authorities will then locate that person and offer them support including finding them accommodation.
In Cardiff alone, the number of people sleeping rough has jumped 64% over the last two years.
"We know some people want to help but don't know what to do," said StreetLink director Matt Harrison.
"People don't know whether they should give people money or food or drink, or talk to people or refer them to local services.
"What is most effective is to get people into local services to help get them off the streets but most people won't know where to go.
"StreetLink has the information and we will get in touch with local services, and then report back to the person who got in touch."
StreetLink has been running in England since 2012 and received funding from the UK government.
More than 35,500 alerts have been made to local services and 15,000 people have received support with almost a fifth gaining accommodation.
Some of the reasons for not being able to help someone is because they have moved on or they were begging as opposed to being homeless.
The rollout to Wales includes funding from the Welsh government.
StreetLink said it is hard to get exact numbers of those sleeping rough around Wales but it estimates the figures run into the hundreds.
A headcount by the Welsh government in November 2014 showed there were 244 people.
Meanwhile, figures published by The Wallich - a charity supporting homeless people in Wales - show an increase of people sleeping on the streets of Cardiff, up from 12 in October 2013 to 28 in October 2015.
Antonia Watson, chief executive at The Wallich, which will receive many of the referrals, said: "So often, members of the public see someone sleeping rough and wonder 'what can I do?'.â€¯
"People in the general population are obviously scared of approaching strangers on the street, concerned about doing the wrong thing, and unsure what to do for the best. Unfortunately this often leads them to do nothing at all.â€¯
"Streetlink solves this issue."
Communities Minister Lesley Griffiths said StreetLink would "provide a lifeline to many of Wales' most vulnerable people, when they need it most".


The UK has insisted it will not grant Julian Assange "safe passage" to Ecuador as it seeks a diplomatic solution to him being given asylum.

Downing Street said the government was obliged to extradite Mr Assange to Sweden where he faces questioning over sex assault claims, which he denies.
The Wikileaks founder has been staying at Ecuador's London Embassy since June.
South American nations have pledged support for Ecuador after the UK said it could legally enter the building.
The Supreme Court in May dismissed Mr Assange's bid to reopen his appeal against extradition and gave him a two-week grace period before extradition proceedings could start.
"We hope that we can reach a diplomatic solution and we are doing what we can to achieve that," Prime Minister David Cameron's official spokesman said.
"Under our law, having exhausted all the options of appeal, we are obliged to extradite him to Sweden. It is our intention to carry out that obligation.
"We will continue talking to the Ecuadorean government and others to try to find a diplomatic solution."
Last week Ecuador described as a "threat" a UK letter that drew attention to the Diplomatic and Consular Premises Act 1987, which could allow it to potentially lift the embassy's diplomatic status to allow police to enter the building to arrest Mr Assange for breaching his bail terms.
The Foreign Office later said the letter had been sent to clarify "all aspects of British law that Ecuador should be aware of".
It has said it will follow its obligations, under the Extradition Act, to arrest Mr Assange if he leaves the embassy.
Meanwhile, a meeting of the Union of South American Nations agreed a document which said it supported the country "in the face of the threat" to its London embassy.
After Ecuador's Foreign Minister Ricardo Patino finished reading the final declaration from the Union of South American Nations (Unasur) summit, he joined hands with his fellow foreign ministers from across South America and raised them aloft.
Ecuador's President Rafael Correa has suggested Mr Assange could co-operate with Sweden if assurances are given that there would be no extradition to a third country.
On Sunday, Mr Assange, 41, used his first public statement since entering the embassy to claim asylum - delivered from a balcony - to call on the US to stop its "war on whistle-blowers".
The US is carrying out an investigation into Wikileaks, which has published a mass of leaked diplomatic cables, embarrassing several governments and international businesses.
In 2010, the two female Wikileaks supporters accused Mr Assange, an Australian citizen, of committing sexual offences against them while he was in Stockholm to give a lecture. He claims the sex was consensual and the allegations are politically motivated.


Olympic 2012 silver medallist Michael Jamieson admits he is "leaning towards" retirement from swimming, but will decide his future in the coming weeks.

The 27-year-old was contemplating life outside the sport while working for the media at the Olympic Games in Rio.
But Dmitriy Balandin's gold in the 200m breaststroke prompted a rethink, as Jamieson swam faster for 2012 silver.
The Scot will only continue racing if he feels he can compete for a Commonwealth gold medal in 2018.
"Going into Rio, I thought being there in a different capacity, just trying to relax, I was leaning towards finishing," Jamieson told BBC Scotland's Sportsound programme.
"I don't want to be an athlete that hangs on and falls down the pecking order, I want to be competing for medals.
"But the time that I swam in London four years ago [2:07.43] was quicker than won gold [2:07.46] in Rio. The time that won the bronze medal [2:07.70], I've done that eight or nine times in my career."
Jamieson was the only British male to win a swimming medal at the London Games four years ago, but he finished second to Ross Murdoch at the Glasgow Commonwealth Games and has struggled for form since then.
He was not selected for the GB team for the World Championships last year, which prompted him to move away from his Bath training base to Edinburgh University, but Jamieson could only finish fifth in the Olympic trials.
In the immediate aftermath, he admitted he was considering retirement, and will make a final decision shortly, with the competitive fire still burning in him.
"Missing out on the team this year was heartbreaking," he said. "It should have been bread and butter for me to make it.
"I certainly don't have another four years in me, to go to Tokyo [2020], so if I was to continue, it would to looking to the Gold Coast and the Commonwealth Games in two years.
"After having won two silvers in the past, I'd only be going there to win. So the question is if my body's capable of doing that. The honest answer is, I don't know, but psychologically I don't want to be involved in the sport if I'm not going to be competing for major medals.
"I feel like I was very close to a decision before going out to Rio and then seeing the standard of times that won the medals in the 200m breaststroke, I thought 'I'm still there, I'm still capable of doing this. That's thrown the cat amongst the pigeons'.
"I've kept myself in really good condition in the past couple of months. I've been doing a lot of strength training, a lot of yoga, a lot of land-based training, so I wouldn't have a problem getting back to 90% fitness, which I feel is where I've been for the last 12-18 months, but it's that other 10% that's missing.
"The swimmers are all on a break just now, but within the next few weeks I need to make a call. I'm just not able to get the same out of my body as I was a few years ago.
"That's quite a bizarre concept, and still something that I'm struggling to get my head around, but my body is not responding to training the same way as it used to.
"Either way, it's going to be a brave decision. I am leaning towards finishing, because I just don't know if I'm able to get to that same level again."
Jamieson said his highlight from the aquatics events at the Olympics was the emergence of 19-year-old University of Stirling swimmer Duncan Scott, who won two silver medals at the Games.
"There was a great shot of Duncan shaking hands with the great Michael Phelps," Jamieson said.
"Duncan is the slightest figure you'll ever see in a swimming pool, he's got a physique like a canoe, so to see him have that moment with Michael Phelps, after having swum faster than he did in the [4x200m freestyle] relay, was really quite special."
Jamieson was also "quite shocked" at the presence at the Games of athletes who had previously been banned for doping events, in particular the Russian swimmer Yulia Efimova, who won two silver medals.
"Efimova has become a scapegoat and a figurehead for the battle against doping," Jamieson said.
"She's served two doping bans, one which we know was cut short to allow her to compete in the games in Rio, and every time she came out and was introduced to the crowd to compete, she was roundly booed.
"It's an Olympic Games, that's just completely surreal and foreign to me to hear that sort of atmosphere."
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China's richest man has opened a massive entertainment complex to compete with US giant Disney.

"Wanda City", in south-eastern city Nanchang, features rides, shopping centres and an aquarium, and cost more than $3bn (just over Â£2bn).
Its owner, Wang Jianlin, said he wanted to move away from western imports and to establish a global brand based on Chinese culture.
Disney is planning to open its own theme park in Shanghai next month.
The new entertainment complex includes an $800m China-themed park filled with twirling "porcelain teacup rides" and bamboo forests, as well as a huge indoor shopping mall, and what is claimed to be the world's largest ocean park.
Mr Wang's Wanda property group has also invested heavily in the film and cinema business.
It has indicated it wants to fend off Disney in the Chinese market and become a global entertainment brand.
In remarks at Saturday's opening ceremony, Mr Wang did not mention Disney by name, but said that after millennia of Chinese cultural domination, the country was lacking confidence in its own culture.
"We want to be a model for Chinese private enterprise, and we want to establish a global brand for Chinese firms," he said.
Only a week ago he told China Central Television (CCTV) that "this craze for Mickey Mouse and Donald Duck is over, the period when we would blindly follow where Disney led has been gone for years."
After the site in Nanchang, Wanda plans to open around 15 in the country by 2020.
Meanwhile Disney's theme park in Shanghai, costing $5.5bn, will be its sixth theme park and its fourth outside the United States after Paris, Tokyo and Hong Kong.


Jodie Whittaker is the new Doctor Who - and the first woman to take the role.

17 July 2017 Last updated at 08:54 BST
Fans watched the announcement on BBC One yesterday, and this is how they reacted...


The High Court has begun hearing the legal challenge of a terminally ill UK man who wants the right to die.

Noel Conway, who is 67 and has motor neurone disease, wants a doctor to be allowed to prescribe a lethal dose when his health deteriorates further.
He said he wanted to say goodbye to loved ones "at the right time, not to be in a zombie-like condition suffering both physically and psychologically".
Any doctor who helped him to die would face up to 14 years in prison.
Mr Conway was too weak to attend the court in person.
His lawyer, Richard Gordon QC, told the High Court in London that Mr Conway faced a stark choice either to seek to bring about his own death now whilst still physically able to do so, or await death with no control over how and when it comes.
Mr Gordon said the change to the law that Mr Conway wanted would apply only to adults who are terminally ill with less than six months to live and who have a settled wish to die.
Mr Conway, of Shrewsbury, told the BBC: "I will be quadriplegic. I could be virtually catatonic and conceivably be in a locked-in syndrome - that to me would be a living hell. That prospect is one I cannot accept."
MPs reject 'right to die' law
British man dies at Dignitas centre
Assisted dying debate: The key questions
Mr Conway, a retired college lecturer, was once fit and active but motor neurone disease is gradually destroying all strength in his muscles.
He cannot walk and increasingly relies on a ventilator to help him breathe.  As his disease progresses, he fears becoming entombed in his body.
Mr Conway is being supported by the campaign group Dignity in Dying, but the issue polarises opinion.
Baroness Jane Campbell - a disability rights campaigner - says changing the law would send all the wrong signals.
The last major challenge to the law was turned down by the Supreme Court three years ago.
It ruled that while judges could interpret the law it was up to Parliament to decide whether to change it.
In 2015 MPs rejected proposals to allow assisted dying in England and Wales, in their first vote on the issue in almost 20 years.
Supporters of the current legislation say it exists to protect the weak and vulnerable from being exploited or coerced.
The case is expected to take up to four days.
Assisted suicide - helping or encouraging another person to kill themselves - is illegal under English law.
Under the terms of the Suicide Act (1961) for England and Wales, it is punishable by up to 14 year's imprisonment. In Scotland, helping someone take their own life could lead to prosecution.
There have been several unsuccessful attempts to change the law, as well as some high-profile cases that have challenged it.
2001: Diane Pretty, who had motor neurone disease, fought a long, and unsuccessfully, legal battle to win the right for her to end her life. She took her case to the European Court of Human Rights, arguing that her husband should be given immunity from prosecution should he help her to die. She lost and died at a hospice near her home in 2002.
2009: Debbie Purdy, who had multiple sclerosis, won a landmark ruling in 2009 when the courts agreed that it was a breach of her human rights not to know whether her husband would be prosecuted if he accompanied her to a Swiss clinic where she could end her life. That prompted Keir Starmer - the then Director of Public Prosecutions for England and Wales - to publish guidelines setting out what was taken into consideration when weighing up a prosecution. Debbie died in a hospice in England in 2014.
2012: Two men suffering from locked-in syndrome lost their legal fight to be helped to die. Tony Nicklinson and a man known only as Martin - both left paralysed after a stroke - had argued that doctors should be allowed to end their lives without punishment. Martin argued that the DPP policy on encouraging or assisted suicide was not clear enough for people such as carers to know how they could provide assistance without the risk of being prosecuted. Tony Nicklinson died in August 2012 after refusing food.
2016: The family of deceased locked-in syndrome sufferer Tony Nicklinson and paralysed road accident victim Paul Lamb lose their right-to-die challenges at the European Court of Human rights. They campaigned that disabled people should have the right to be helped to die with dignity.


Hundreds of slippery fish scattered all over a busy road in Scotland.
A van shed its load of fish as it was making a delivery.
Drivers faced long delays as they were cleared up.
It was pretty smelly though.


US department store firm Macy's has cut its profit outlook for the year after a drop in sales in the third quarter.

Macy's net income for the period between August and October was $118m (Â£77m), down from $217m in the same period last year.
Shares in the company fell 14% following the news.
In a statement, Macy's chief executive Terry Lundgren said the company was "disappointed" that the pace of sales did not improve as much as expected.
Sales were hurt in part by the warm weather, which made it harder to sell winter clothing, and a strong dollar, which hurt tourist spending.
"Heading into the fourth quarter, we are shifting our organisation into overdrive to focus on sales-driving activities in the holiday shopping season," said Mr Lundgren.
The company now sees full-year earnings coming in at $4.20 to $4.30 per share, compared with an earlier guidance of $4.70 to $4.80.
Macy's has opened five discounted outlets in the New York area and plans to open a sixth before the end of the year.
The company, which also owns the department store Bloomingdale's, plans to open three new discount branches of that store too.
Macy's said it is also considering discounts at its stores to help move large quantities of inventory.
On a call with investors chief financial officer Karen Hoguet said "we will need to liquidate this inventory in the fourth quarter so that we can maintain the flow of fresh new merchandise."
Macy's has been cutting down on the number of standard priced stores that it owns for the last several years. Earlier this year it announced plans to close 35 to 40 stores in the US in early 2016.


Nicola Sturgeon has put independence "on the back burner" while focusing on getting Scotland the best Brexit deal possible, an SNP MSP has said.

Joan McAlpine told a conference that the first minister's priority was Scotland's relationship with the EU.
Ms Sturgeon has said a fresh referendum is "highly likely", with predecessor Alex Salmond predicting a vote in 2018.
Opposition parties have called on Ms Sturgeon to rule out a second referendum altogether.
Ms McAlpine was taking part in a conference run by the Centre on Constitutional Change examining Scotland and Brexit alongside fellow MSPs and members of the European and external relations committee, of which she is the convener.
The Scottish government is considering its options for future relations with the EU after the UK voted to leave in June, with Ms Sturgeon recently launching a "fresh conversation" on independence.
The panel were questioned about whether there was likely to be an independence referendum before the UK completes its exit from the EU.
Ms McAlpine said: "I don't know if there would be an independence referendum before then.
"Everything that the first minister has said so far suggests that an independence referendum is very much on the back burner, and the priority just now is to secure the best possible deal for Scotland.
"One of the difficulties is that we don't actually know what Scotland's position is going to be within negotiations.
"That's something that we're going to explore with the committee, in terms of what are the inter-government relationships going to be, is Scotland just going to be a consultee, or are we actually going to be fully engaged in shaping the deal?"
Labour's Lewis Macdonald, who is deputy convener of the Europe committee, said people have "had enough of referendums".
He said: "There are no certainties in any of this, but I think we're getting pretty close to certainty when I say that no, I don't think there will be an independence referendum before the start of 2019, nor do I think British withdrawal from Europe will be complete by then either.
"In terms of the independence referendum, the one thing that Nicola Sturgeon has been consistent about is that she has no intention of calling an independence referendum until she thinks she can win. And there's no evidence at all that that position has changed."
Tory MSP Jackson Carlaw agreed that the Brexit talks would take some time, noting that there were a number of major elections in key EU member states in coming years.
He added: "For all the rhetoric that goes about, I don't expect there to be another independence referendum any time soon, if at all, frankly."
However, Green MSP Ross Greer said the Brexit talks could yet lead to a second independence poll if the UK government opts for a "hard" deal, such as one involving a break from the single market.
He said: "I think there probably will be a second independence referendum, particularly if the UK is heading towards a hard Brexit. It's debatable whether we are, we simply don't know that yet. The hints I would say are that we are.
"It's obviously a very distinct possibility, and I would say that in that set of circumstances the situation here in Scotland does change utterly."
He added: "I do think it is likely that there will be a second referendum - the challenge is timing. There's a very compelling case that you have it as soon as possible in the Article 50 process to give you time for what are two separate but interrelated sets of negotiations with Europe, one for Scotland becoming independent in Europe and one for the UK leaving.
"But there's the obvious political argument that you would want to wait and build support for independence before calling a referendum. I don't envy Nicola Sturgeon's position in making that choice."
Lib Dem Tavish Scott said he thought there was a better case for a second EU referendum than one on Scottish independence, arguing that people "did not know what they were voting for" in the Brexit poll.
He also said he did not think the UK would be out of the EU by 2019.
He said: "I think Mike Russell has been appointed [as Scotland's Brexit minister] not just for this parliament but for the next one as well. The idea that this is all going to happen quickly is not in the real world of EU politics, never mind UK politics."


The jury in the trial of a man accused of carrying out a string of sex attacks on elderly people in south London has retired to consider its verdict.

Delroy Grant, 53, is allegedly the attacker dubbed the Night Stalker, who carried out a series of rapes and sex assaults on 18 victims over 17 years.
Mr Grant, of Honor Oak, denies 29 charges, including burglary, rape and sexual assault at Woolwich Crown Court.
The court heard his vulnerable victims were targeted in their homes at night.
The attacks took place in Warlingham, Shirley, Beckenham, Bromley, Addiscombe, Orpington and West Dulwich.


Kilmarnock manager Lee Clark says the club were powerless to prevent striker Josh Magennis leaving to join Charlton Athletic.

The Northern Ireland international signed a two-year deal with the English League One side.
''I know Kilmarnock fans will be gutted Josh has left," said Clark.
''It's a terrific move for Josh, financially he'll get a much bigger offer than we could ever offer him.''
Kilmarnock rejected three bids from Charlton for Magennis but finally accepted an offer reported to be around £250,000 on Thursday.
''The club didn't just take the first offer that came in for Josh, we did everything we could to keep him," Clark explained.
"But when it becomes apparent that the player's heart is set on the move then it's about getting the best possible deal.''
The Killie boss would like to use all the money from Magennis' sale to strengthen his playing squad, but accepts that is unlikely to happen.
''Of course I want every single penny. The club have already banked the cash so I want the interest as well.
"I'll always be greedy as a manager, but as a club we have to be run on a firm financial footing.
''I'll have to sit down with the board of directors and see what I can use, not just in terms of the transfer fee but also in terms of Josh's salary. He was one of the club's highest earners so we'll need to see what we can use.''
''Fans are entitled to want all the money used and that would be my ideal scenario but reality steps in and we have to act accordingly.
"There are some targets we believe we can get and from now until the end of the transfer window that's what we're looking to do."


Eight construction firms have announced the launch of a scheme aimed at compensating workers who were victims of past blacklisting in the industry.

Under the scheme, workers on the list would be paid ??4,000 on a fast-track basis rising to ??20,000 if they can prove discrimination. In more serious cases, up to ??100,000 could be awarded.
But the scheme has been denounced as "a PR stunt" by the GMB union.
The existence of blacklisting in construction was revealed in 2009.
In March of that year, the Information Commissioner's Office uncovered a list drawn up by a firm called the Consulting Association, based in Droitwich.
At the time, the ICO seized a database containing the names of 3,213 construction workers and environmental activists used by 44 companies.
The Consulting Association (TCA) has since been closed down.
The scheme, to be known as The Construction Workers Compensation Scheme (TCWCS), is now accepting applications and will remain open for two years.
The companies involved are: Balfour Beatty, Carillion, Costain, Kier, Laing O'Rourke, Sir Robert McAlpine, Skanska UK and Vinci PLC.
"All eight companies recognise that the activities of TCA were unacceptable and regret their involvement." said a statement issued by TCWCS.
"They are sorry that information was held about individuals and for any hardship suffered as a result."
But GMB national officer Justin Bowden said the scheme did not go far enough and said the sums of money involved were "grossly inadequate".
"This cut-price compensation offer is not an act of genuine contrition, it is a PR stunt," he said.
"The eight companies between them have a turnover of over ??34bn and pre-tax profits of ??1.04bn. They can afford to own up, clean up and pay up."
Under the fast-track process, workers whose names appeared on TCA's list are eligible for ??4,000 in compensation, rising to a maximum of ??20,000 "when there is evidence that the records had been accessed to the applicant's detriment". The money will be paid within two weeks.
Those who can prove that being blacklisted had an impact on their employment can choose to go in for a full review process, which will take three to six months. Under this part of the scheme, claimants can receive up to ??100,000.


Businessman Wei Ming Shi was out walking with his wife when three muggers tried to snatch her bag.

"I fought them off but they hit me in the face and broke my nose," he said. "My vision was blurred for a week afterwards.
"These kind of attacks happen all the time, especially to Asians," said Mr Shi, who runs a driving school in the Belleville neighbourhood of Paris and has been mugged twice.
"My wife has had her mobile phone stolen at least five times," he said. "Every day people are being attacked and beaten up, so we're scared."
Ethnic Chinese residents of the French capital say they are being systematically attacked and robbed - and they are campaigning for more police protection.
This is in an area which, until recently, was held up as a model of multi-cultural harmony.
Chinese community leaders say at least one robbery is being committed each day, often accompanied by gratuitous violence.
The numbers are confirmed by municipal officials and residents of the city's 20th arrondissement, or district, where many of the muggings take place.
The problem has become so bad that thousands of members of this normally shy community have been demonstrating on the streets, calling for tougher policing.
Local officials are not unsympathetic and the police say they have put extra officers on the streets.
But budgets are limited and residents say there still are not enough patrols, especially when they are most needed, at night, when the streets are deserted.
The mayor of the 20th district, Frederique Calandra, said she believed the attacks were not motivated by racism.
"Chinese people are attacked very often, not because of racist problems but because thugs have this opportunity of making money easily, because Chinese people are used to carrying cash - a lot of cash," said Ms Calandra.
The Chinese may have become targets because they are seen as relatively prosperous. Some of them run shops or restaurants, and it is hard for them to avoid carrying large amounts of cash after they close their businesses for the day.
Officials say the muggers are often of immigrant descent themselves, from other communities.
The Chinese association spokesman, Olivier Wang, says most of the attacks are violent, even when the targets are women.
"This is happening because of poverty, but it's unbearable," Mr Wang said.
He said a Chinese man who tried to film a recent mugging in Belleville on his mobile phone was attacked by the muggers and beaten up so badly that he is now in a coma.
Mr Shi says people are terrified of being assaulted. "Our problem isn't so much that money or phones are being stolen, it's the violence we can't stand."
Many Parisians are shocked that the attacks are happening, not in the notoriously violent suburbs - the banlieue - but in the city itself.
Hamou Bouakkaz, a deputy mayor of Paris, says things have degenerated in the past two years following the economic downturn.
"Belleville was a very universal melting-pot, but the government has cut budgets allocated to integration, to security," Mr Bouakkaz said.
Mr Shi showed me photographs of people who had been mugged. One was of a woman, with bruised eyes, cuts on her face and a blood-soaked dress.
Another showed a man with cuts around his eyes.
He also produced a thick sheaf of copies of police reports of muggings. There were more than 80, covering a period of less than a year.
But many victims do not report attacks to the police, because they are illegal immigrants or cannot speak French well.
Those who do report muggings say the perpetrators are rarely brought to justice. The police declined to comment on this.
Community worker Dominique Dardel, a member of the neighbourhood council, says the long-term solution is not more police on the streets.
"Those who carry out these muggings usually grow up spending a lot of time on the streets," he said.
"Early on they realise that society isn't really offering them a future. The schools have to change their approach to these kids and convince them that they can have a future. That's the key."
But for now, victims like Mr Shi say the muggings are getting more violent, and they are fed up with living in fear.


Josh Turnbull has signed a two-year contract extension with Cardiff Blues until the end of the 2017-18 season.

The Wales international back-rower, 27, began the new season by scoring a hat-trick of tries in Sunday's Pro12 victory over Zebre.
Turnbull, who has won seven international caps, said the arrival of new coach Danny Wilson over the summer was a "big factor in me staying".
"We're looking to build something special," he said.
Wilson worked with Turnbull during their time at the Scarlets and feels the forward will play a significant role this season.
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"He is a real leader, someone who puts his body on the line and is a fantastic professional," said Wilson.
"He displays all the values that we are looking for in players who represent Cardiff Blues.
"Josh has repeatedly proven his quality at both regional and international level. He remains a very ambitious player and the fact he has signed a new contract is testament to what we are striving to achieve here."
The Blues recently gave captain and fellow back-rower Josh Navidi a new three-year contract.


England face a nervy last day in the final Test as they seek a first series victory in India for 27 years.

The tourists, who lead the series 2-1, need a draw in Nagpur and ended the fourth day 165 runs ahead on 161-3.
After India declared on 326-9, England stumbled to 94-3 in their second innings, losing Alastair Cook, Nick Compton and Kevin Pietersen.
But Jonathan Trott (66 not out) and Ian Bell (24 no) steadied England with a watchful partnership of 67 runs.
"England will have to bat into the afternoon because even if they score 60-70 by lunch, they'll still need a few more runs. What Dhoni did at the start of the day was quite puzzling as they got stuck in no-man's-land for an hour and didn't really push the game along. The key for England was that no matter how slowly they batted, they didn't lose too many early wickets. Dhoni set defensive fields, only had two men catching for the spinners, which is all right in theory providing you get wickets, but they only got three throughout the day. Trott has scored delightfully, he's looked at ease and has scored relatively quickly, while Bell has played sensibly for once."
The Warwickshire pair will be key to England's chances of batting themselves into a safe position on the fifth day, against an Indian side desperate to level the series.
Trott, who relishes such situations, looked assured at the crease as he expertly combined his famed powers of concentration with a fluency which brought nine boundaries, while Bell was equally as resilient as he looks to return to form after scoring just 56 runs in five previous Test innings on tour.
One of Trott's boundaries came in unusual circumstances as Ravindra Jadeja let the ball slip out of his hand during his delivery stride. The ball bounced numerous times before landing in the short leg area and being smashed for four by the opportunistic Trott.
With Joe Root and Matt Prior, who shared a 103-run partnership in the first innings, still to bat, England will be confident of staying at the crease long enough to secure the result they need to match the achievements of their predecessors in 1984-85.
However, they will also be aware of the dangers a batting collapse could bring and the threat of an Indian run chase on a pitch that still offers very little to the bowlers.
The hosts can sense the match and series are slipping away, though, judging by a fiery evening session which saw a number of their players exchange words with Trott.
The animosity stemmed from an unsuccessful appeal when Ishant Sharma thought he had the batsman caught behind.
Alastair Cook is now England's leading Test run-scorer in India with 863, one ahead of Mike Gatting, with Tony Greig in third place and Kevin Pietersen fourth
If Trott did get an edge it was virtually impossible to judge, and umpire Kumar Dharmasena's decision to turn down India's vociferous appeal was the correct one.
Mahendra Dhoni's side felt aggrieved and sledged the unperturbed Trott for the final hour of the evening session, but England, and captain Alastair Cook in particular, are the ones who should be feeling hard done by.
After putting on 48 for the first wicket with Compton, Cook, who made 13 from 93 balls, was given out caught behind off Ravichandran Ashwin despite replays showing the skipper's bat was nowhere near a ball that spun sharply.
Compton followed for 34 just before tea - given out lbw to Pragyan Ojha - and when Kevin Pietersen played no shot at a straight one from Jadeja and was bowled, England were in a spot of trouble.
However, the assured intervention of Trott and Bell steadied any nerves and blunted the Indian attack.
Dhoni may now rue the hour he wasted at the start of the day's play, when the Indian tail added just 29 runs in 13 overs to get within four runs of England's first innings total.
Listen to match highlights and Jonathan Agnew and Geoffrey Boycott's analysis of the day's play on the Test Match Special podcast.
We are using archive pictures for this Test because several photo agencies, including Getty Images, have been barred from the ground following a dispute with the Board of Control for Cricket in India, while other agencies have withdrawn their photographers in protest.


Four people have been rescued after their yacht got into difficulty off the County Antrim coast.

The vessel's engine failed a mile north east of Muck Island on Thursday evening.
Weather conditions at the time were described as good with a Force 3 wind and a slight swell running.
A volunteer crew from the Larne RNLI launched two lifeboats at about 18:30 BST.
The lifeboat towed the yacht to Carrick Marina.
Larne RNLI Deputy Launching Authority Philip Ford-Hutchinson said the call-out was "a great example of both our inshore and all-weather lifeboats working well together to assist the four people onboard the casualty vessel".


The trial of a Londonderry man charged with committing terrorist offences in the Middle East could be dismissed if there are any further delays, a judge has said.

Eamon Bradley, from Benview Estate in Coshquin, was arrested in October 2014, after he returned from Syria.
He faces charges including providing training in the making of or use of firearms in Syria.
On Thursday his preliminary hearing, set in December, was due to take place.
However, the prosecution told Londonderry Magistrates' Court that the case could not go ahead without consent papers signed by the Advocate General in London.
The prosecution said those papers had been sent, but had not yet returned to Northern Ireland.
The defence told the court that the delay was "not acceptable" as Mr Bradley had been on bail for a long period of time.
In response, the judge issued what is known as a 'McAleenan warning', which gives him the power to refuse to return a defendant for trial if there are long delays in the case.
The judge told the court he was not stating that he would refuse to return Mr Bradley, but warned the prosecution to delay the case no further, telling them to "get on with it".
He added: "I am sure the Advocate General or whoever is extremely busy but they could have found time to scrawl their signature on the papers."
The date for the preliminary hearing was moved to 3 March.


It's a curious thing to see a group of early whale foetuses up close - to see beings so small that have the potential to become so big.

But what really strikes you, especially in those initial developmental stages, is how familiar the forms look. How like an early human foetus, they appear.
"This is something you see time and time again in vertebrates, not just with mammals," says Richard Sabin, the Natural History Museum's top whale expert.
"You see these similarities in the early developmental stages and it's really not until you're halfway through the gestation - which  for a humpback whale is around 11 months - that you start to see the things that make that foetus characteristically the species that it is."
Richard has a remarkable sequence of seven humpback foetuses that he's going to put on display for the NHM's major summer exhibition on cetaceans.
They go from what is essentially just a ball of cells that's perhaps only a few weeks old, all the way through to a specimen that appears to be a perfect humpback in miniature.
This larger foetus, about half a metre in length, is probably seven to eight months into the gestation period. It has everything you would expect to see in a humpback, including those long, tell-tale pectoral flippers with their nobbly tubercles.
The specimens were collected at the beginning of the 20th Century by scientists who had been sent to the Antarctic to gather data on the activities of the whaling fleets.
Their role was to understand the biology, the movements, and the ecology of whales - to appreciate the status of stocks so that the commercial returns could be maximised. It's an awkward feeling knowing that these foetuses were taken from harpooned pregnant humpbacks.
Somehow you have to console yourself with the recognition that the acquired data was ultimately what shut down that bloody industry.
"There is a story with every specimen and it may not be a very comfortable story, but it is something we have to acknowledge," says Richard.
"The thing to remember is that the data we get from these specimens we actively use for marine conservation purposes now."
Just this past week, a Swiss-led team used old whaling data to show how species had shrunk in size in the 40 years prior to the stocks collapsing. This trend signal, the team said, could be used to warn of imminent disaster in other hunted wildlife groups.
What have we learned from foetuses, specifically? A lot it seems about evolutionary biology.
"One thing we see in these humpbacks is the development of tooth buds at around four-to-five months into gestation. They're then reabsorbed to allow the baleen to start to develop," explains Richard. The baleen are the keratin plates that hang from the upper-jaw and filter the humpbacks' prey.
"So, we know from the study of these foetuses, from an evolutionary developmental perspective, that there was a time when all cetaceans were toothed and that baleen are a relatively recent development. And we've only just found the fossils that back that up."
The whales exhibition is due to open on 14 July, the day after the NHM re-opens its front entrance. The Hintze Hall has been remodelled. Its emblematic diplodocus ("Dippy") dinosaur is being replaced by a blue whale skeleton that will hang from the ceiling (Plot spoiler: I've had a sneak peek already and it looks spectacular).
So, it's certainly a timely moment to highlight the contribution of cetaceans to life on Earth.
More than 100 specimens from the London museum's collections are being set up in the institution's Waterhouse Gallery.
The exhibition will impress upon visitors the huge diversity of whales, dolphins and porpoises. It will explain their relatively short evolutionary journey, from being land animals 50 million years ago to becoming the well-adapted ocean-dwellers we know today.
And it will describe how they move, how they breathe, and how some echolocate to find their prey. It still astounds me that whales can communicate over many hundreds of kilometres.
"We want people to realise that as well as being mammals like us, they also have complex culture like us," says Richard. "This is a very new area of study that has accelerated in just the past 10 years through observations, through genetic information and the data coming from museum specimens."
Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos


An ex-News of the World reporter convicted of using a soldier in Prince Harry's regiment as a paid source has had his conviction quashed by the Court of Appeal.

Ryan Sabey, 35, was accused over payments to Paul Brunt, 33, while working at the now-closed Sunday paper.
Mr Sabey was found guilty of aiding and abetting misconduct in a public office.
But the Lord Chief Justice quashed the conviction on the grounds that the jury was misdirected by the trial judge.
And Lord Thomas also confirmed there would be no retrial.
Director of Public Prosecutions Alison Saunders had already said she would not pursue the case.


An academy and free school trust praised by the Prime Minister has paid its chief executive a second salary passed through two separate companies, a government report says.

It raises serious concerns about financial management and governance at Perry Beeches Academy Trust.
The trust has been issued with a financial notice to improve following a probe prompted by a whistleblower.
Labour accused the government of having "snuck out" the report.
The trust, which runs five secondary schools in Birmingham, and has been praised by senior government ministers, has been ordered to improve financial management and governance.
The Education Funding Agency investigation followed whistleblower allegations that the trust's chief executive, Liam Nolan, was paid an additional salary through a supply company, Nexus Schools Ltd.
The findings confirmed the trust paid Â£1.2m over two years to Nexus, which then passed some of the money to Mr Nolan through a company of which he was sole director.
There was no written contract for the payment and no alternative tenders for the services were considered, said the report.
"The trust pays Nexus for providing the services of a CEO for Perry Beeches multi academy trust.
"Nexus then sub contracts this role to Liam Nolan Ltd," says the report.
These payments, of at least Â£160,000 over two years, were not disclosed in financial statements, it says.
They are on top of Mr Nolan's annual payroll salary of Â£120,000 for his executive head teacher role.
It concludes that the trust was therefore in breach of the Academies Official handbook, the Charities Commission Statement of Recommended Practice and the Academies Accounts Direction.
Not only was there no written contract but there was no formal procurement exercise to demonstrate value for money, the investigators found.
In the past the trust has drawn praise from Prime Minister David Cameron. education secretary Nicky Morgan and the former education secretary, Michael Gove.
Last year, Mrs Morgan cited Perry Beeches as an example of schools achieving "truly extraordinary outcomes for young people".
Mr Cameron opened one of its new schools in 2013, describing the chain as "a real success story" while Mr Gove said the trust ran two of the best schools in the city.
A Department for Education spokeswoman confirmed the trust had been issued with a financial notice to improve following an investigation.
"The Trust has already put in place an action plan and is working with us to urgently fix the weaknesses we found.
"We will monitor progress closely, and if we don't see significant improvement we will not hesitate to take further action."
The spokeswoman maintained that the strict system of oversight and accountability under which trusts operate is "more robust than in council-run schools, which has enabled us to identify these issues and take swift action to address them."
But Labour's shadow minister for schools, Nic Dakin, said the findings were evidence that the government had "completely failed to put in place the appropriate checks over academy chain funding decisions.
Instead it had prioritised converting schools into academies over school standards and the protection of public money.
"It is extremely concerning that so much taxpayer money is ending up in the pockets of academy chain directors and trustees.
"Labour will fiercely oppose this top-down, costly reorganisation of our schools, which nobody wants and schools don't need, ensure there is proper oversight of all our schools, and put local parents and communities at the heart of decisions when it comes to their children's schools."
Liam Nolan Ltd is appointing a voluntary liquidator according to the Companies House website.
Notices posted relating to the company also include a special resolution to wind up and a declaration of solvency.


Tommy Wright asserted that Michael O'Halloran will still be a St Johnstone player "in the morning", with Rangers "seriously interested".

No agreement has been reached and, as things stand, Wright is planning to play O'Halloran in next weekend's League Cup semi-final with Hibernian.
O'Halloran set up a goal as Saints lost 3-1 to Premiership leaders Celtic, who went six points clear at the top.
"The latest is that there has been no change," said Wright.
O'Halloran started on the right flank before moving up front in the second half. He did not play last week, after news of Rangers' interest broke, because Wright felt he was not in the right frame of mind.
There was enough about his game to create an equaliser at Celtic Park, though, for Steven MacLean.
"Michael's our player and we can't stop clubs asking a question about him," Wright told BBC Scotland. "He played because all week he's been excellent in training.
"When it emerged and really hit the press last week, it did have an effect on him. But he's in a good frame of mind.
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"The chairman came down on the bus today and unless something's happened, Michael's still our player, so that's the only update I can give.
"I'm confident that he'll be our player in the morning. He's contracted to us for another 18 months.
"We do know that Rangers are seriously interested. There's a valuation and if that's met then he'll no longer be our player. I'll be preparing, come Monday, for him to be in the team for next week."
Wright was happy with O'Halloran's performance, and aspects of the team's display as a whole, despite the defeat.
"We put a lot into game," he said. "First goal, they get a little break with the deflection. But we should see it out to half-time when we get the equaliser.
"We conceded the second goal at a bad time. At the start of the second half we looked okay, we put Michael up top, but the third goal kills us.
"I thought it was a foul on Brian Easton, [Gary] Mackay-Steven's foot was high and I was disappointed the ref didn't give it.
"You need those situations to go for you, then to compound it [Craig] Gordon makes a great save from Liam Craig moments later.
"I'm pleased with how we played, but there are still things we could do better; retention of the ball. But you have to work so hard here to get the ball [that] at times you don't keep is as much as you would like.
"The attitude, organisation and desire was good, I just thought at times we won the ball back then gave it away too cheaply."
Celtic manager Ronny Deila was pleased with the way his side "controlled" the game and the number of chances they created.
Mackay-Steven scored twice, Stuart Armstrong also found the net and Deila believes his team will be hard to catch if they maintain the same level of performance.
"We play much more forward now and we're hard to beat because we have a lot of quick players in the team," the Celtic manager said.
"[Mackay-Steven] was very good. Stuart and him were very good, the full-backs were vey good coming forward, so there was a lot to build on there.
"We're going to be very hard to beat when we are playing so direct and with pressure, everybody working so hard and then we win the ball in good situations."


Cyclists have been warned in both Latin and ancient Greek not to chain their bicycles to a fence near Cambridge University colleges.

The notice, outside a house in Portugal Place, bears transcriptions in both classical languages stating cycles will be "removed or destroyed" if parked.
But it drew criticism after a picture was posted online, with some pointing out mistakes in the Greek message.
Others said the presence of a bike suggested the sign "hadn't worked".
It is not known how long the warning, behind a building previously used by the Greek Orthodox Church, has been in place.
Classicist Prof Mary Beard, from Newnham College, said the Latin part of the sign translates as "two wheels [cycles] left/abandoned here will be removed".
Selwyn College classics lecturer Dr Rupert Thompson said: "It's trying to say, 'bicycles left here will be destroyed'."
He agreed there were inaccuracies in the Greek warning.
"It's definitely trying to be ancient Greek but it's not quite.
He said both lines of the Greek had used the wrong letters, while one word carries the opposite meaning to that apparently intended.
"The second word, 'ΛΗΦΘΕΝΤΕΣ', actually means 'taken' not 'left'," he said.
"I don't know what to make of it really, but it's very amusing and it's absolutely great to see this in the city."
Both Prof Beard and Dr Thompson, however, agreed the Latin and Greek interpretation of the word "bicycle" was correct.
"Two wheels" was, they said, the best way to describe a bicycle, which was not invented until the early 19th Century.
Many commenting on Twitter called the sign "elitist", while one wrote: "I feel tempted to add some Anglo-Saxon graffiti."


American gymnast Simone Biles produced a stunning performance to win the women's all-around Olympic gold medal.

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Biles, 19, who has won 10 World Championship medals since 2013, scored 62.198 to win her second Olympic medal by a margin of more than two points.
Compatriot Alexandra Raisman got silver with Russia's Aliya Mustafina third.
Great Britain's Ellie Downie came 13th, narrowly missing out on becoming the best performing female British gymnast in an Olympic all-around final.
Biles, described by many as the greatest ever gymnast, had arrived in Rio as the overwhelming favourite for gold and the 4ft 8in athlete delivered in a big way.
Having already led the United States to victory in the team event, she turned the spotlight on her individual brilliance with a dazzling display of power, agility and gravity-defying moves.
She went ahead after the first of four disciplines with a score of 15.866 on vault, although she dropped back to second with 14.966 on the uneven bars, with Mustafina taking the lead at the halfway point.
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Biles then turned on the style with an acrobatic beam routine that included a stunning spin to score 15.433 before a floor routine to samba music packed with energetic tumbles, including the move that bears her name.
She scored 15.933 for that final routine and burst into tears when the victory was confirmed.
The United States have now won this event four times in a row, following victories by Carly Patterson in 2004, Nastia Liukin in 2008 and Gabrielle Douglas in 2012.
Biles has more chances for success in Rio as she is also in the vault final on Sunday, the beam final on Monday and the floor final on Tuesday.
Britain's Max Whitlock had won a bronze medal in the men's event on Wednesday, but Downie's medal hopes ended with a poor score on her third apparatus, the uneven bars, before she made another error on beam.
Find out how to get into gymnastics with our special guide.
Those mistakes saw her drop down from seventh to 13th, to miss out on emulating her sister Becky Downie, who came 12th in the all-around final at the 2008 Olympics in Beijing.
Seventeen-year-old Ellie Downie, the winner of the BBC Young Sports Personality of the Year award in 2015, gained a total of 56.883 after scores of 14.300 on floor, 15.100 on vault, 13.783 on uneven bars and 13.700 on beam.
Gold medallist Simone Biles said: "I'm very excited and relieved, I've finally done it. You never know the feeling until it hits you.
"I'm not the next Usain Bolt or Michael Phelps, I'm the first Simone Biles. To me I'm just the same Simone."
Silver-medallist Alexandra Raisman added: "No-one goes into this thinking they can beat Simone.
"I'm sure most people don't go into it thinking they can beat Usain Bolt, so it's kind of the same thing.
"We are like sisters. I told her before today, I want you to win and I want second."
Great Britain's Ellie Downie said: "I was really happy with how floor and vault went. On bars I lost a bit of concentration, which is something I'll learn from.
"On beam I didn't feel nervous and the actual routine was really good but the landing I needed to focus more.
"It's mixed emotions knowing if I had gone clean I had a chance of a medal, which shows I'm right up there. That's a big positive to take out of these Games.
"It's been a bit of a rollercoaster experience but I'm very proud of what I've achieved."
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Michael Dunlop will hope to bridge a four-year gap since his last Ulster Grand Prix win when he competes at the Dundrod road races this week.

The last of Dunlop's six successes at the event came in the 2013 Superstock race but the 15-time TT winner will be fancied to add to that tally.
"We've made changes to the Superbike to get more speed and are developing it all the time," said the Ballymoney ace.
"It's a fast, smooth and open. On a good day it's a fantastic circuit."
Since taking Supersport and Senior triumphs at the Isle of Man TT in June, Dunlop has enjoyed victories at the Southern 100 and Armoy but the Bennett's Suzuki and MD Racing pilot will face stiff opposition at Dundrod.
Lincolnshire's Peter Hickman goes into the meeting on a high after securing a win and a second place at Sunday's British Superbike round at Thruxton on board his Smith's BMW machinery.
Hickman, who occupied the top step of the podium for the first time at an international road race by winning the second Superbike race at 'the Ulster' in 2015, believes Ian Hutchinson's one-year-old lap record of 134.089mph can be surpassed.
"I definitely think we could go a lot faster. It all depends on the conditions obviously but if we can have a couple of godo days of practice and get to Saturday with some good laps under our belt then I don't see why we can't push it up to maybe 135 or 136mph," said the two-time Macau Grand Prix winner.
"It'd be great to have a lap record around a road circuit, apart from my newcomer record at the TT I've not had an outright lap record anywhere on the roads so it'd be nice to do something like that, and good to do it at the Ulster.
"I enjoy riding on the roads so much, it's so much fun, and I also enjoy the British Superbikes, and I'm fast doing both which is why I get so much excitement from both. For me it's all about riding bikes as much as possible.
"Dundrod is just an untouched, proper circuit, just as it should be. It's fast, it's flowing, it hasn't had to be adapted with chicanes to try and make it safer; it already is as safe as you can make a road race, even though it is ridiculously fast," added the 30-year-old, who achieved five podiums from five starts at this year's TT.
Among the other leading challengers should be Bradford rider Dean Harrison, who was crowned Southern 100 Solo Champion for the first time on his Silicone Engineering Kawasaki in July.
Bruce Anstey will hope to make up for a disappointing season so far as he goes in search of a 13th win on board his fleet of Padgett's Hondas, with another former lap record holder, Manxman Conor Cummins, his team-mate once again.
William Dunlop's best chance of victory is likely to come in the Supersport class, while Fermanagh's Lee Johnston will aim to recapture the form which saw him clinch a hat-trick in 2015 as he returns to action after a practice spill at the TT.
Dan Kneen will hope to make the most of the opportunity he has been handed to impress in the Tyco BMW outfit, with Derek Sheils, Ivan Lintin, James Cowton, Jamie Coward, Dan Cooper, Christian Elkin and Adam McLean other probable frontrunners.
Roads closed - Wednesday and Thursday 9 and 10 August - 10:00 BST to 21:30 BST; Saturday 12 August - 09:30 BST to 20:30 BST
Thursday racing - Dundrod 150 - Race 1 - Dundrod 150 National Race (5 laps); Race 2 - Ultralightweight/Lightweight (5 laps); Race 3 - Dundrod 150 Challenge (5 laps); Race 4 - Dundrod 150 Superbike (6 laps); Race 5 - Dundrod 150 Supertwins (5 laps)
Saturday racing - Ulster Grand Prix - Race 1 - Superstock (6 laps); Race 2 - Supersport (6 laps); Race 3 - Ultralightweight/Lightweight; Race (5 laps) Race 4 -  UGP Superbike (7 laps); Race 5 - Supertwins (5 laps); Race 6 - Supersport (6 laps); Race 7 - Superbike Race (6 laps).


It has been a long journey and not always a straightforward one.

For the past decade or so, I have been writing stories about the return of trains to the Borders but, of course, the struggle started long before that.
Indeed, you could argue that the battle really began back in 1969 - or even earlier - when the Waverley line through the region was closed.
On the night when the final train set off from Edinburgh there was a demonstration in Galashiels station.
There were also protests at Melrose and Hawick.
Despite the opposition, the sound of a train pulling up at a station would be absent from the Scottish Borders for the next four decades and more.
There were regular rumbles of discontent in between times and they started to take more solid form at the end of the 20th century.
In 1999, the Campaign for Borders Rail was formally launched at a Burns Supper in Melrose Station.
It subsequently gathered thousands of signatures on a petition pressing for a route to the region to be reopened.
And, in 2000, an independent study concluded that the reopening of the Borders rail link could be financially viable.
The gears of progress were slowly clicking into motion and, five years later, a Holyrood committee supported the case for reopening the line.
Then, in 2006, the bill was approved which would pave the way for work to finally begin.
At that time a Â£155m price tag was attached to the project with a forecast opening in 2011.
However, there were soon problems in meeting both that deadline and budget and it emerged that both would be missed.
By 2008, the estimated costs had risen to between Â£235m and Â£295m and the opening date was pushed back two years.
Work officially started in 2010 but there were still a few twists and turns in store.
Three groups were selected to submit tenders for the work but as companies dropped out of the process that plan had to be scrapped.
Instead, the Scottish government decided that Network Rail could take the project forward.
Despite these apparent setbacks, the major clearance and constructions works continued along the length of the line from Tweedbank to Edinburgh.
All along the route, there were now clear indications that transport between the capital and the Borders was being transformed as stations, bridges and new road layouts slotted into place.
And, although the completion deadline was once again put back to 2015, the reality of the scale of the scheme was really starting to sink in.
Then, last year, a symbolic moment was reached as the track laying began.
As machines slowly rolled along the route, it became clear that the decision which had so incensed many people nearly half a century ago would finally be reversed.
Some have said it does not go far enough and would like to see the line extended back to Carlisle where it used to reach.
Others have concerns about turning south east Scotland into a commuter belt for Edinburgh or question how much effect it will have in more remote parts of the Borders.
But what cannot be doubted is what a historic moment it is for this part of the country.
A region which has gone without railway stations for so long will now have no fewer than three.
One long journey which started in the late 1960s has been completed and now many more - lasting an hour at most - can be undertaken.


The second round of the Niger presidential election takes place on Sunday 20 March, and the result may have implications for regional stability and the fight against Islamist terrorism in West Africa.

Incumbent President Mahamadou Issoufou looks set to secure a second term in office, as opposition candidate Hama Amadou has been evacuated from prison to France for specialized medical treatment just days before the run-off, raising concerns over the poll.
The former parliamentary speaker and prime minister has been in detention in the south-western town of Filingue since November 2015 over allegations of baby trafficking. He has dismissed the charges as politically motivated.
Niger is seen as a key ally in the fight against Boko Haram, and President Issoufou has been praised in the West for rallying neighbouring countries to fight the group.
President Issoufou seems poised for victory in the run-off, having narrowly missed outright victory in the first round with 48% of the vote.
Having garnered only 17%, it will be difficult for Mr Amadou to bridge the gap despite the opposition alliance backing him. Mixed messages about a poll boycott are also likely to weaken his chances.
It is still unclear if the Opposition Coalition for Change (COPA 2016) - an alliance formed to back Mr Amadou - will take part in the vote, having announced a boycott.
The opposition has said it will not recognise the outcome, saying Mr Amadou's imprisonment prevented him from campaigning, among other complaints; while the government's handling of his medical condition is a sensitive issue that could inflame tensions.
The nature of Mr Amadou's illness is not clear, but the government says he has "a chronic illness which he has suffered from for three years". The 66-year-old received medical treatment for an eye condition recently.
On 14 March, he reportedly lost consciousness before being revived at the prison clinic, his doctor telling a local TV station that he had fainted.
The doctor was later arrested for "revealing medical confidentiality and spreading false news".
On 16 March, it was reported that Amadou had been flown to France for "specialist treatment", with the government claiming that he was suffering from "general fatigue".
The opposition has made conflicting statements about their participation. On 8 March, COPA 2016 announced its withdrawal on account of "irregularities and massive fraud".
However, the coalition reportedly did not consult Mr Amadou about the boycott, and his camp later asserted that he would take part in the vote.
The Independent National Electoral Commission (CENI) says the opposition candidate's name will be on the ballot because he had not formally withdrawn his candidacy by the cut-off date of 10 March.
The governing Niger Party for Democracy and Socialism (PNDS) says the vote will proceed with or without the opposition, accusing its rivals of fearing "dismal defeat".
More about Niger
Niger is fragile and its stability is at stake as one of the poorest countries in Africa.
It also finds itself on the frontline in the fight against jihadist group Boko Haram, and Mr Issoufou has been active in rallying a regional force against the group.
The president claimed to have foiled a coup against him in December, and military officers and opposition leaders were subsequently arrested.
Seen as a key ally of the West in ongoing counter-terrorism operations in the vast Sahel region, the incumbent president has been described as one of French President Francois Hollande's "most loyal African partners".
It has also been attacked by al-Qaeda in the Islamic Maghreb.
A vast, arid state on the edge of the Sahara desert, Niger is rated by the UN as one of the world's least-developed nations.
BBC Monitoring reports and analyses news from TV, radio, web and print media around the world. You can follow BBC Monitoring  on Twitter and Facebook.


First-time buyers are £1,440 a year better off with their own home, Bank of Scotland research has found.

The average monthly buying cost, including mortgage payments, associated with a first-time buyer of a three-bedroom house was £525 in December.
That was £120 lower than the monthly rent of £645.
This resulted in an increase of £659 over the last year - with 2014's figure for the saving associated with buying instead of renting being £781.
The Bank of Scotland said the difference had grown as a result of average monthly rents rising by £46 compared with a £9 decrease in monthly buying costs.
It also revealed the gap between buying and renting had widened significantly over the past five years, with the annual saving almost treble the £548 recorded in 2010.
Over this period, the average rent had grown by 20% while buying costs had increased by 7%.
The last time renting was the cheaper option was in 2008.
Nicola Noble, mortgage director at Bank of Scotland, said: "Since 2009, average buying costs have consistently been lower than average renting costs. In the past year this gap has doubled to an annual saving of £1,440.
"Of course, it was not always like this. In 2008, buying was more expensive than renting, but record low mortgage rates, coupled with rising private rents, have made getting on the housing ladder financially more attractive for those able to raise the necessary deposit and with access to mortgage finance.
"This improvement in the costs of buying compared to renting over the past few years has helped to boost the number of first-time buyers, who now account for 46% of all home sales in 2015 - up from 35% in 2007.
"Official government schemes such as Help to Buy have also played a part in helping first-time buyers, as have improving economic conditions."
The latest figures show the number of first-time buyers in Scotland is estimated to have totalled 27,900 in 2015, accounting for 46% of all house purchases made with a mortgage.


A teenage Liverpool fan was "taken by the crowd" during the Hillsborough disaster, the new inquests have heard.

David Mather, a 19-year-old post office clerk from Huyton, Merseyside, attended his team's FA Cup semi-final against Nottingham Forest with friends.
They told the jury that David was pushed forward as the crowd pressure on the Leppings Lane terrace intensified.
Mr Mather was one of 96 supporters fatally injured in the crush at the Sheffield stadium on 15 April 1989.
He drove to the match with four friends - Alan Woods, Mark Garratt, Alan Benson and Peter Wilkinson - who all survived.
They arrived at the ground at 12:30 BST, two-and-a-half hours before kick-off, and went into pen three, a fenced enclosure behind the goal at the Leppings Lane end.
The jury heard parts of a statement written by Mr Wilkinson in 1989 in which he described how the group managed to stay together until about 14:55.
Mr Wilkinson said: "Suddenly there was a steady build-up of pressure from behind that took me further forward.
"There was no release in the pressure at all. It got to such a stage that I couldn't move anything except my feet. It was as if I was floating.
"By this time people were shouting and screaming all around me. The pain was quite intense and I was having difficulty breathing.
"By this time the people in our group had all got separated. I had no idea where David Mather had gone.
"The last I saw him he was moving down towards the front but I lost sight of him and became too concerned with what was happening to myself and what was happening around me."
Mr Woods said in his statement that Mr Mather "looked as if he was being taken by the crowd" and he shouted 'Come back, Mather!' but received no response.
He told the jury it did not seem like his friend was in pain or discomfort, adding: "When I said 'Come back, Mather!', it would have been more to be back with us, rather than he was in any danger at all."
Mr Garratt said whenever his group went to matches together, they would try to stand in a line just in front of a crush barrier.
On the day of the disaster, though, he said "as things built up and built up, it became harder and harder to... maintain that position".
He added: "He wouldn't have chosen to go forwardâ€¦ because we would have tried to stay in a line, in a group."
Mr Garratt said he also called out to Mr Mather: "Where are you going?".
He said that was not because it looked like his friend was in danger but because "we all want to stand together".
The jury saw video footage of Mr Mather inside pen three between 14:46 and 14:53, showing how he was initially close to his friends and then moved further towards the front.
He was next seen in a video timed at 15:22, being carried on to the pitch and laid in the recovery position by Sgt Adrian Brazener from Nottinghamshire Police.
A St John Ambulance volunteer medic, believed to be Elaine Bunting, and Prof Timothy Cooke, a professor of surgery who was at the match, are believed to have tried to resuscitate Mr Mather on the pitch.
A doctor who assessed casualties inside the temporary mortuary after 16:00 confirmed Mr Mather's death.
The jury heard how his aunt, Patricia Cotton, travelled from her home in Manchester to Sheffield that evening and identified Mr Mather's body from Polaroid photographs taken of the dead.
The inquests, in Warrington, Cheshire, are due to resume on Thursday.
BBC News: Profiles of all those who died


Workers at Tata Steel's Port Talbot plant have been meeting with the new UK secretary of state for business, Greg Clark.

Tata has paused plans to sell the site, which currently employs 4,000 people.
The Indian company is working on keeping its UK business as part of a joint venture with German conglomerate ThyssenKrupp.
Roy Rickhuss from the Community union said he was "encouraged" by the visit.
Mr Clark was appointed head of the new Department for Business, Energy and Industrial Strategy on 14 July as part of Prime Minister Theresa May's cabinet reshuffle.
Mr Rickhuss said: "I am encouraged that Greg Clark has met with steelworkers in his first week on the job.
"He will have left today in no doubt that Community will keep the pressure on this government to keep their promises to protect the steel industry.
"The new secretary of state clearly understands the scale of the challenge still facing the industry, but his words to steelworkers today must be followed by firm actions to help save their jobs.
"By visiting Port Talbot, he will have seen first-hand that the highly skilled workforce is the foundation on which any success for this industry will be built."


Cardiff City's Malaysian owners have detailed for the first time the £100m investment pledge for squad strengthening, debt repayment and upgrading facilities.

In a statement, owner Tan Sri Vincent Tan said a further £35m would be pumped into the club over the next 12 months, taking the investment to £75.8m.
Around £10m is to be earmarked to settle the outstanding Langston debt.
And £22m will go on training facilities and increasing the stadium capacity.
The announcement comes just days after the Championship club said they were going ahead with plans to rebrand the club, including changing the kit from blue to red and introducing a new badge incorporating a Welsh dragon.
The colour change, which has divided opinion among fans, is part of the investment pledge, with the owners insisting the use of a dragon will expand the club's appeal in "international markets" and "will give this club a new focus and dynamism".
Tan insisted he appreciated the change was "extremely emotional and for some quarters remains difficult to understand".
But he said: "I would like to emphasise that I hold no desire to trample on club history or heritage and would be saddened if supporters thought that this was my intention."
And he added: "There is no reason why any existing supporter needs to feel disenfranchised. This is and always will remain your club."
Cardiff City have missed out on promotion to the Premier League through the play-offs in the last two seasons.
The owners hope the significant cash for squad strengthening will help their bid for top-flight status and end what they say is an operating loss of £1m a month.
In the statement, Tan confirmed: "Cardiff City is expecting a cash injection in the amount of £35m to meet its financial obligations for the period from now until May 2013, including a substantial amount for squad strengthening within budgets.
"Of this amount, £10m has been earmarked to settle the longstanding Langston debt, which if accepted by Langston will go a long way to cleaning up the balance sheet of the club.
"This further £35 million cash injection coupled with my earlier investment of £40.8 million will add up to a very sizeable £75.8 million invested in the club.
"In addition to this, we have budgeted £10 million for the new Premier League standard training facilities and £12 million to increase the stadium capacity by an additional 8,000 seats to 35,000 seats.
"Add this further £22m CAPEX [capital expenditure] and our investment in Cardiff City will have ballooned to £97.8m. With a contingency provision of another £2.2m and our total investment will reach £100m."
Cardiff manager Malky Mackay has already urged the fans to back the revolutionary plans and Tan said he hoped this latest investment would help Cardiff realise their Premier League dream.
"Over the course of the last two years, including some memorable home games and two trips to Wembley Stadium for matches being watched by millions worldwide, I sincerely believe that my investment has not been wasted even though we are still chasing that dream of making it to the Premier League," he said.
"I believe that our club has great potential, but in order to realise that potential real world business and financial decisions need to be made at the appropriate and opportune time."