A scheme to demolish the old Vickers tank factory in east Leeds and dig out coal from underneath has been "approved in principle" by councillors.

The plan is for the former Barnbow Works near Cross Gates to be demolished and the coal extracted.
About 2,700 objections have been made, but the scheme was approved with conditions attached.
Councillors said a relief road must be built taking traffic away from Crossgates before any work could start.
The planning panel was told the foundations of both the former tank factory and other buildings, which had previously been demolished at the site, would have to be removed.
Once this work was completed then a 150,000 tonne seam of coal, thought to be about  6ft 6in (2m) deep, would be removed to stabilise the site.
Plans for the site to be subsequently used for housing would then be considered.
In a briefing document the councillors were told: "Demolition of the buildings and breaking up of the concrete is clearly necessary in order to be able to redevelop the site for housing."
It is expected to take two years to construct the relief road to the former tank factory site.


Colchester United will be relegated from League Two if they do not improve after 10 winless league games, says their forward Kurtis Guthrie.

After Saturday's loss at Yeovil, the U's' slipped into the relegation zone.
"It's a shambles. It's nothing to do with the management. They do their best to prepare us," the 23-year-old said.
"We're looking like kids out there, we're getting battered, we're throwing games away, we can't see games out. It's not good enough."
He continued to BBC Essex: "If you're lying to yourself, then you're going to get worse. We'll get relegated if this carries on."
Guthrie's opening goal had given Colchester a second-half lead at Huish Park, before the Glovers struck twice late on to take all three points - leaving the Essex side without a league win since 10 September.
Guthrie moved to Colchester in the summer from Forest Green Rovers and said he "did not come for a relegation battle".
But, having been relegated from League One last season after three previous campaigns of bottom-half finishes, Guthrie says the side should take note of other clubs that have slipped down the divisions.
"If you look at the club over the last few years it's been the same. It's almost like a cancer and we need to cut it out. If you don't you keep falling away.
"You've seen what happens to teams like Stockport, they fall away and keep going and they're not coming back.
"We as the players have to take ownership, take the criticism and use that as motivation to go and do well and not shy away from the fact we are doing bad at the moment."


Great Britain's men suffered their second Olympic defeat as Australia claimed a 2-1 victory.

GB goalkeeper George Pinner scrambled to save a Blake Govers shot in the second quarter to keep the scores level at half-time.
However Aran Zalewski sliced home in the fourth quarter, before Jacob Whetton nudged a second over the line.
GB's Ashley Jackson hit a late strike but the team slipped to fourth in Pool A before Friday's game against Spain.
The top four from each pool of six progress to the quarter-finals, which begin on Sunday.
"We came out wanting three points and we nearly salvaged a draw at the very end," said goalkeeper George Pinner.
"It is disappointing but it is the first time in this tournament we have really put up a proper performance and that is something we can build on going into our last game against Spain where we should know what we will have to do to get through".
The men were aiming to join Great Britain's women in qualifying for the quarter-finals, with the women having beaten Argentina 3-2 earlier in the day.
Although Australia had won just one of their pool games before the match, the World Cup winners were stronger as the game progressed.
Brazil suffered their fourth defeat of the tournament in Pool A, as Nick Wilson struck four times to give New Zealand a 7-0 victory.
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Two firms have been fined a total of £550,000 following the death of a diabetic hospital patient injected with insulin syringes containing no insulin.

Neil Judge, 58, from Barnsley, South Yorkshire suffered organ failure when he was injected with saline.
He was being treated at Sheffield's Northern General Hospital in 2010.
Sheffield Crown Court heard how the faulty syringes were supplied by wholesalers Fresenius Kabi Ltd for manufacturers Calea UK Ltd.
The Medicines and Healthcare products Regulatory Agency (MHRA) said Mr Judge's multi-organ failure was triggered by diabetic ketoacidosis because his body was deprived of insulin for more than 13 hours.
Last year, Sheffield coroner Chris Dorries ruled ketoacidosis from the manufacturing error was a "major contributory factor" in Mr Judge's death.
Fresenius Kabi, of Eastgate Way, Manor Park, Runcorn was fined £500,000 with costs after pleading pleading guilty to breaches of the Medicines Act 1968.
Calea UK, of the same address, was fined £50,000 with costs after pleading guilty to similar breaches, the agency said.
The MHRA said Calea also manufactured a batch of pre-prepared syringes administered to a patient with cystic fibrosis at the Royal Shrewsbury Hospital in 2011.
They were prepared and delivered direct for the patient and were found to contain three times the prescribed daily dose. There were no lasting effects in this case.
The court was told the two incidents followed a series of inspections by MHRA officials that highlighted deficiencies at the Calea and Fresenius Kabi site.
Alastair Jeffrey, MHRA head of enforcement, said the two companies were "equally responsible for the medicinal failure" that contributed to Mr Judge's death.


Nigeria's interior minister has said the army is making progress in the war against Boko Haram militants, despite the killing of 44 people in a mosque.

Abba Moro dismissed the attack as "desperate" and "isolated".
"The security agencies of Nigeria have been able to push the Boko Haram sect from their major strongholds," he told the BBC's Focus on Africa programme.
Nigeria has declared an emergency in three states after thousands of deaths in militant attacks in recent years.
Boko Haram is fighting to establish an Islamic state in Nigeria's mainly Muslim north.
By Will RossBBC News, Lagos
If this was Boko Haram, it might appear baffling. Many churches have been bombed but why would a group that wants to impose Islamic law across Nigeria open fire on worshippers at a mosque?
In fact this would not be the first time Boko Haram has targeted a mosque  - Muslim clerics have also been killed because of their views.
The gunmen may have known that amongst the worshippers were members of the vigilante groups that have sprung up to help the army defend the population.
Three months ago the military campaign was launched. But the Islamist militants have not been defeated - over the past month more than 160 people have been killed in attacks on boarding schools, army and police bases as well as a Christian-dominated area of Kano City. Other attacks go unreported. So what is the way forward?
One Borno state official suggests the only solution is to deploy more vigilante groups.
The mosque attack happened during dawn prayers on Sunday, although news only emerged on Monday, as communications have been disrupted by the state of emergency.
It took place in the town of Konduga, 35km (22 miles) from the Borno state capital, Maiduguri, where Boko Haram was established in 2002, launching its first attack seven years later.
Twelve further civilians were killed at Ngom village, closer to Maiduguri, reports say.
Boko Haram has not commented on the mosque attack but news of it came as a video emerged of the group's leader, Abubakar Shekau, saying his followers had carried out recent attacks including some that targeted the police and the military.
He said this showed that the army's claims to have inflicted heavy losses on the group were "lies".
It is not clear why the mosque was targeted - one explanation is that members of a local vigilante group may have been praying there.
Several such groups have been set up since the emergency was declared in Borno and two neighbouring states in May.
Boko Haram frequently attacks churches but it has also occasionally targeted mosques and preachers disagree with their views.
The attackers wore military uniforms, officials say, which they may have taken during recent attacks on a barracks.
Following a lull immediately after the emergency was declared, there has been a recent spate of attacks, blamed on Boko Haram, which have left some 160 people dead.
But Mr Moro said these were the "desperate antics" of a group trying to show it was still relevant.
Thousands of extra soldiers have been sent to the region since the state of emergency was announced.
The military cut mobile phone networks when they imposed the state of emergency, saying they wanted to make it more difficult for the militants to organise attacks.
However, some local officials have said this prevents civilians from getting help.


Legislation that would have set minimum standards for passenger space aboard commercial aeroplanes has failed to pass in the US Senate.

In recent years, airlines looking for cost savings have reduced the sizes of seats and cut the amount of passenger legroom, among other changes.
Passengers have often complained about the increasingly cramped quarters.
Some flights have been disrupted after disputes broke out among passengers because of seating arrangements.
"It costs you an arm and a leg just to have room for your arms and legs," said Senator Chuck Schumer, who sponsored the amendment, which was attached to a broader aviation bill.
Many airlines now charge passengers if they want more legroom.
Under the legislation, airlines would have been barred from further reducing the "size, width, padding and pitch" of seats. It also addressed legroom and the width of the aisles.
Airline companies opposed the bill saying the measure was attempting to "re-regulate" the industry.
The amendment failed 42-54 with all but one Republican voting against the legislation.


A newspaper in India has offered its readers scientifically unfounded tips for ensuring they conceive boys instead of girls, telling would-be mothers to eat lots and face west while sleeping.

The sex of a child is determined by the chromosomes in the father's sperm.
But the daily newspaper Mangalam, in Kerala state in southern India, printed six suggestions for those who want to have baby boys.
There is a cultural preference for male children in India.
"The chance of a girl or a boy at conception is totally random," said Dr Shazia Malik, a consultant obstetrician and gynaecologist at The Portland Hospital in London, debunking the article.
"There is no scientific evidence on any method that will change this statistical chance when a baby is conceived naturally."
Mangalam, which filed the story in the health news section of its site, also advises potential mothers-to-be not to skip breakfast and to have sex only on certain days of the week, when the male sperm is "stronger". It said men can play a role and help strengthen their sperm by avoiding acidic foods.
But the strength of a sperm does not affect the baby's sex. The only way a baby can be male is if the fertilising sperm carries a Y chromosome.
Feminist Indian website The Ladies Finger translated the article from the original Malayalam language, which is spoken in Kerala.
"With all these inconvenient laws regarding sex determination, it is a relief that there is finally a fool-proof checklist to follow for boy-bearing," The Ladies Finger site wrote, sarcastically.
Tests to determine a foetus' sex are illegal in India, but that does not stop them taking place and leading to sex-selective abortions.
In 1961, there were 976 girls for every 1,000 boys under the age of seven. According to the latest census figures, released in 2011, that figure had dropped to 914.
Gita Aravamudan, Indian author of Disappearing Daughters: The Tragedy of Female Foeticide, said Mangalam's article is not likely to have a major impact, especially as it is written in a minority language, but it is one of many articles, "remedies" and old wives' tales that offer ways to avoid having a female baby.
"This article is even more ridiculous than usual, but such ideas are common," she told the BBC.
"It shows that attitudes like this still flourish despite initiatives taken by the Indian government, NGOs and health workers. The message isn't going through: people still value boys more than girls."
The preference for boys is longstanding in some cultures, and often comes from men being seen as the stronger sex and financial providers for families, especially during parents' old age.
In India, dowries, paid when girls eventually marry, are also seen as a high cost that could be avoided.


It was a normal school day in May when Stephen and the 80 or so pupils were packed into classroom number 8 in South Sudan.

But as the children listened to the words of their teacher, soldiers from the rebel forces surrounded the school's pale-blue, concrete classrooms.
Stephen describes being frozen with fear as the rebel fighters took him and more than 100 of his classmates.
They were given no choice. They were now the latest young recruits, in South Sudan's bloody civil war.
The United Nations says the recruitment of children in South Sudan's on-going civil war is "rampant". It estimates that there are 11,000 children serving in both the rebel, and government armies.
We met Stephen, and three other boys with similar stories, who are all aged between 12 and 17.
One boy recalled how they "were forced to train, and if we didn't want to do it, we were beaten heavily".
"When we were moving and boys got sick and died they would just be left where they fell," said one of the boys, aged 14.
One boy asked the soldiers why he had to join their army.
"To defend your tribe," came the reply.
When they were sent to fetch water and fire wood, the boys escaped, walking for days.
They hid at night by tying themselves to the branches of trees to sleep, for fear of being found.
Eventually they reached a UN camp at Bentiu, in northern South Sudan where they are trapped.
If the boys leave the camp and travel the short distance into the nearby town they risk being spotted by soldiers and punished as deserters, in an increasingly brutal war.
When you walk along the long corridor-like-market at the edge of Bentiu camp where the boys live, group after group of wide-eyed, young, smiling children will crowd around the lens of your camera.
But this is a harsh world for any child to grow-up in.
Every day they wade, some in their AC Milan or Arsenal football shirts, through the muddy, faeces-infested floodwaters that have turned much of their camp into a swamp where 47,000 people live in endless rows of white tarpaulin tents.
Beyond the relative security of the camp's gates, the only schools in the nearby town are abandoned, or occupied by soldiers, because of the on going fighting between Government and rebel forces.
In a climate where children have little or nothing to do, they are "vulnerable" to being recruited by either side in the war, says Ainga Razafy, from the United Nations Children's agency, Unicef.
It is easy to spot children carrying guns on the dusty, pot-hole-infested road that runs through the ramshackle town, a short distance from the camp.
"They are obviously associated with the armed conflict," says Ainga Razafy.
According to Unicef around 70% of an estimated 11,000 child soldiers are serving with rebel groups, including the notorious White Army, known for sending thousands of children into battle.
The rebels are fighting the fledgling government of South Sudan, which was itself born out of a rebel movement that spent decades fighting Sudan, and finally won independence in 2011.
But after years of trying to release some of an estimated 20,000 former child soldiers called "Lost Boys" from the army, the current government's ranks are again swelling with minors.
Within days of abducting Stephen, this soft-spoken, fidgety and wide-eyed little boy was on the frontlines of South Sudan's civil war.
It was not possible to get a comment from a rebel spokesperson for one of the many rebel groups accused of using children to fight, but South Sudan's national army, known as the SPLA, admits it has recruited some boys into its ranks.
SPLA spokesman, Colonel Philip Aguer, confirmed that 149 children had been recruited in the Bentiu area.
He said SPLA commanders were working to discharge those children, and insisted the SPLA was no-longer recruiting boys into its ranks.
But the UN says that forced recruitment of children continues to this day, and estimates there are around 3,300 children serving in the SPLA.
Colonel Aguer says that this "is not true" and that some children may have been counted twice.
He believes that when the rebels "make mistakes" the UN and other foreign agencies were sometimes guilty of "generalising the blame".
But with limited access, international aid workers across the country told the BBC that the 11,000 figure was a rough figure thought to be hugely underestimated.
Although the boys we met were forcibly recruited into South Sudan's war, there are other factors that drive children into military ranks.
A 12-year-old boy recently told Unicef child protection specialist Sylvester Ndorbor Morlue that he wanted to join the military simply because he felt "it was the best place" to be.
"Some of them see it as employmentâ€¦ and parents are sometimes pushing (their children into the military)."
Whenever the conflict escalates, the demand for military manpower increases, and children are often targeted in a country where nearly half the population is under 15.
As the rain subsides and the floodwaters fall, the slight improvement in conditions will be welcomed by the hundreds of thousands of people living in South Sudan's camps.
But outside, the dry season allows the movement of troops and military hardware.
And the fear is armies that, despite recent peace talks in neighbouring countries, show little sign of peacemaking on the ground, will enforce their rules of war on the young, and claim more of South Sudan's little lives.
The names of the boys quoted at the beginning of this article have been changed for their protection.


Scotland's First Minister Nicola Sturgeon has warned of a "strong backlash" if Scotland were to be taken out of the EU by a UK-wide referendum.

The SNP leader used a speech in Brussels to say a vote to take the UK out of the European Union could cause a "groundswell of anger" in Scotland.
Prime Minister David Cameron has promised an in/out EU referendum.
At the start of her address, Ms Sturgeon paid tribute to former Lib Dem leader Charles Kennedy who has died.
She said: "It's a dreadfully sad day for Scottish and UK politics. The news about Charles Kennedy is stunning and absolutely tragic.
"Charles was one of these rare things in British politics, he was a brilliant and effective politician, perhaps one of the most talented politicians of his generation. And yet somehow he managed to be universally liked."
Ms Sturgeon added that Mr Kennedy would have been a "big voice" in the forthcoming European referendum, which will take place before the end of 2017.
Turning to the substantive element of her speech, the first minister said Scotland had much to offer the EU and "much to learn" from the example of its smaller member states.
She called on Mr Cameron to agree to a "double majority" which would mean all four nations of the UK must back withdrawal before exit is possible.
Her speech comes days after Mr Cameron met a number of European leaders to canvass their views on reforming the European Union ahead of the UK vote.
In her first EU address as first minister, Ms Sturgeon said that "positive changes" could be made from "within the existing treaty".
She also raised the issue of Scotland's long-running legal bid to have a minimum price for alcohol.
The Scottish government is locked in a legal battle with Europe over setting a minimum price of 50p per unit of alcohol.
The Alcohol (Minimum Pricing) (Scotland) Act 2012 was passed by the Scottish Parliament in June 2012.
However, it has not yet been enacted due to a legal challenge filed with the Court of Justice of the European Union.
The Scottish government embarked on minimum pricing because it said the "alcohol problem in Scotland is so significant that ground-breaking measures are now required".
Ms Sturgeon's said: "The EU should focus on areas where joint working and co-operation will make a tangible difference to the lives of its citizens.
"In some areas, that means that the EU should leave member states with the autonomy to tackle pressing problems.
"Public health is a relevant example for Scotland and for other countries. Some years ago, the Scottish Parliament voted to introduce minimum pricing for alcohol, to tackle alcohol harm in our society.
"Our ability to do that has been challenged, and is currently being considered by Scottish courts and the Court of Justice of the European Union.
"We know from their support for our case that many other member states support us. My view is that the Commission and EU policy should recognise that.
"They should give a higher priority to enabling member states to take the decisions they deem necessary to protect life and promote health."
However, Scottish Conservative MSP Annabel Goldie said Ms Sturgeon's speech only served to "highlight the contradictions in the SNP's policies in relation to the UK and the EU".
She added: "Whatever the cost, she wants to end our union with the United Kingdom.
"Yet, whatever the cost, it appears she wants to keep our union with the European Union.
"The first minister needs to come clean. Since she is so opposed to the UK and so supportive of the EU project, surely she should just admit that the SNP would dump the British pound and back the Euro."


Reviews are in for the new Spider-Man film, and they're mostly positive.

The Mail calls Spider-Man: Homecoming "the blockbuster of the summer", while The Guardian calls it a "light, snappy and frequently hilarious crowdpleaser".
According to Screen Daily reviewer Tim Grierson, British actor Tom Holland - a former star of the Billy Elliot musical who turned 21 this month - "makes for a believably underage Peter Parker".
The Hollywood Reporter, though, says "a charming new lead only goes so far".
Jon Watts' film, writes critic John DeFore, is "often frustrating" and "represents a creative mis-step" for the Marvel Studios.
Largely set in New York, Spider-Man: Homecoming follows on from Holland's introduction to the "MCU" - Marvel Cinematic Universe - in Captain America: Civil War.
That 2016 film saw Spider-Man - a teenage crime-fighter who can spin webs and swing between tall buildings - participate in a battle between Captain America, Iron Man and other superheroes.
The new film sees Spider-Man's alter ego Peter Parker juggling his high school responsibilities with his secret life as a masked vigilante.
It is not long before he encounters Adrian Toomes, a villainous arms dealer who has his own alter-ego in the form of wing-sporting marauder Vulture.
Previous versions of the Spider-Man franchise featured Tobey Maguire and Andrew Garfield in the title role.
According to Digital Spy, "Spider-Man: Homecoming's biggest achievement is that it makes you forget it's the third different Spider-Man - and second reboot - in less than 20 years."
"There's a spontaneous charge to the film, a euphoric innocence, that makes it a much-needed antidote to stale franchise formula," raves Rolling Stone's Peter Travers.
Variety's Owen Gleiberman, meanwhile, praises the "sinister, gnashing personality" Keaton brings to his role while wishing he had been "given more to do".
"Homecoming is easily the best Spider-Man film since Sam Raimi's operatic Spider-Man 2," concludes Empire's Nick De Semlyen, one of several critics to give the movie four stars out of five.
Spider-Man: Homecoming opens in the UK and Ireland on 5 July.
Superhero movies are like garishly costumed buses at the moment. If you happen to miss one, there's always another one just around the corner.
That's partly down to the way character rights have been divvied up between the studios, who all want a piece of the comic book pie.
Spider-Man is a case in point. He was created in 1962 by Marvel, now a subsidiary of Disney. But he's effectively owned by Sony, who have made five Spider-Man films since 2002.
The success of the Avengers films, though, has inspired Sony to loan him back to Marvel, allowing him to share the screen with the likes of Captain America and Iron Man.
It's a strategy that reaps dividends in Spider-Man: Homecoming, which features Robert Downey Jr's Iron  Man in a supporting role and humorous cameos from Chris Evans' Captain America.
Yet the film also works satisfyingly as a stand-alone superhero teen movie, mostly thanks to the immensely likeable Tom Holland.
The young British actor - not to be confused with Rev's Tom Hollander - has a pleasing boyishness and excellent comic timing in a film that is laugh-out-loud funny when it's not noisily thrilling.
Michael Keaton is also good value in a villainous role that ingeniously plays on his work in both 1989's Batman and the Oscar-winning Birdman.
There is an unexpected moment midway through Spider-Man: Homecoming that had last night's press audience at the Odeon Leicester Square in London bursting into spontaneous applause.
The film is not without faults and is at least 20 minutes too long. Given how familiar the genre has become, though, it speaks volumes that the film still has the element of surprise.
Follow us on Facebook, on Twitter @BBCNewsEnts, or on Instagram at bbcnewsents. If you have a story suggestion email entertainment.news@bbc.co.uk.


The Lawn Tennis Association plans to hand out 10,000 free racquets and offer 10,000 free junior tennis courses in an attempt to unearth stars of the future.

The LTA says it will also take the Davis Cup trophy on a tour to 50 different venues around Britain.
The move follows criticism of the LTA from world number two Andy Murray for failing to develop world-class talent.
Britain won the Davis Cup for the first time since 1936 by beating Belgium in Ghent in November.
"We want to make a difference in capitalising on this unique opportunity to get as many kids on court as possible," said victorious Davis Cup captain Leon Smith.
The lessons will be delivered by a team of 1,000 "expert and passionate coaches", according to an LTA statement.
The opportunity for children and families to take up the offer will go live before the Davis Cup first round tie against Japan in March.


Access to the BBC's English-language website has been blocked across China, the corporation has said.

BBC Global News director Peter Horrocks said it appeared to be "deliberate censorship", adding that the BBC was complaining to the authorities.
Other major news websites were functioning as usual, and the reason for the blackout remained unclear.
Since the 2008 Beijing Olympics, the BBC's English-language site has been generally available.
However, other BBC services including its Chinese-language news website has been blocked largely since it was launched.
BBC World TV - as with all overseas broadcasters - suffers intermittent blackouts particularly when reporting China stories.
Mr Horrocks said: "The BBC provides impartial, trusted news to millions of people around the world, and attempts to censor our news services show just how important it is to get our accurate information to them."
The last time the BBC's English-language website was disrupted was during the corporation's coverage of activist Chen Guangcheng's escape from house arrest in April 2012.


The spectacular, flat landscape that dominates the left side of Pluto's icy "heart" can now be explained, say scientists.

Sputnik Planum is the most prominent feature on the diminutive world, covering 900,000 square km.
Broken into an array of polygons, it is devoid of any impact craters.
Reporting in the journal Nature, the researchers say that roiling cells of nitrogen ice remove any blemishes, maintaining a super-smooth appearance.
They argue that a competing idea, that the polygons are a consequence of cooling and contraction akin to giant "mud cracks", does not fit with the observations.
"It's a vigorously - from a geological point of view - churning layer of solid nitrogen, and it's [as if] the heart of Pluto is truly beating," said Prof Bill McKinnon from Washington University in St Louis, Missouri.
The assessment is based on the data acquired by the US space agency's New Horizons probe, which made the historic first flyby of Pluto last July.
Two separate teams have looked at the information from that encounter and have come to broadly the same conclusion - that only overturning ice, driven by the dwarf planet's internal heat, can produce the cellular terrain.
The polygons are typically about 10-40km across, tiling a deep basin that is surrounded by high mountains.
Each cell is domed, standing some 50m above its edges. Those edges then give way to troughs that can reach 100m in depth.
New Horizons found the planum ices to contain mostly nitrogen, with limited amounts of methane and carbon monoxide.
At the temperatures that persist on Pluto's surface (an extremely frigid -235C), this material is still capable of flowing.
Modelling work suggests just a few centimetres per year of horizontal movement in the tops of the domes would be sufficient to re-surface them in short order - significantly faster than the likely rate of impacts from bodies falling on to Pluto.
"From the calculated average velocity of convection, about 1.5cm per year, we compute the time needed for the ice surface to renew itself, and therefore the maximum age of the surface of Sputnik Planum, to be about one million years," report Alex Trowbridge, from Purdue University, Indiana, and colleagues in the second of the two Nature papers.
Convection requires energy, of course. And the scientists say this would come from radioactive elements incorporated into Pluto at its formation, and which should still be producing the necessary heat to promote the rise and fall of ice within the cells.
There are, however, scaling laws for convection that describe the relationship between the width and depth of convective cells. Taken at face value, these might imply the basin in which the polygons are sitting to be 10-20km deep.
This is somewhat deeper than expected for the underlying basin, but Bill McKinnon and colleagues invoke an idea they call "sluggish lid convection". This sees the dome surface move at a much slower pace than the deeper, warmer subsurface. If this operates at Pluto, the convection system could be much shallower; perhaps 3-6km deep, says Prof McKinnon.
"It all depends on the rheology - how nitrogen ice responds to pressure, temperature and other factors. The stuff at the top moves much more slowly because it's colder. It's 37 degrees kelvin (-236C). It's only modestly warmer down below but it's enough to make the nitrogen ice move," he told BBC News.
Sputnik Planum was without doubt one of the standout discoveries of the New Horizons flyby.
It is the place where geologically recent activity on Pluto is most evident.
Glaciers of nitrogen ice are observed to move away from the water-ice mountains, into the plain.
Giant boulders are carried by some of these ice streams. And because water-ice floats on nitrogen ice, the mountain fragments tend to collect in the polygons' troughs, unable to sink with the downward flow of convection. This gives the appearance of chains of hills.
Although no impact craters are seen on Sputnik Planum, there are fields of kilometre-scale pits, particularly in its eastern and southern regions. These are sectors where there is no convection.
The stagnant ice here likely vaporises over time to produce the pits. It is all part of the process that cycles nitrogen between the plain, the atmosphere, the mountains, and back into the plain via the glaciers.
Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos


Former England batsman Geoffrey Boycott blasted "a pathetic display of batting" as they collapsed to 107-8 on day two of the final Ashes Test at The Oval.

Boycott said on BBC Test Match Special: "There was some really, really bad cricket. Three of them were out pulling or hooking.
"You need to know when to attack and when to defend, but England have committed hara-kiri."
England have already won the series but Australia lead this game by 374 runs.
Boycott continued: "If I was the chairman of England cricket, I'd be going in to talk to the coaches. I'd want to know what you're going to do about this. Because if you don't solve it, I will - I'll get somebody else.
"England will follow on tomorrow and it will be all over by Saturday night."
The hosts had reached 46-1, having lost captain Alastair Cook when he was bowled by a turning delivery from Nathan Lyon for 22.
But that was the cue for his side to lose seven wickets for 46 runs in 22.3 overs - with the manner of nearly every dismissal drawing Boycott's ire.
"Adam Lyth grafted and played nicely, but Peter Siddle came on, his second ball was a loosener, a lollipop outside off stump and he went to pull it and it looped to mid-on. Your career is at stake here," he said.
"Jonny Bairstow came in and they set the trap for him - they put two back and he knocked it straight down his throat.
"Then Ben Stokes came in - almost every second or third ball he was whooshing at it, almost as if he was trying to win the match.
"Jos Buttler is like a rabbit caught in the headlights of Ashes cricket. A seven-year-old schoolboy would have played better. He hasn't made a run all series.
"He hasn't shown any application whatsoever. It looks to me like his mind and confidence is shot for Test cricket - it's pathetic."
Pace bowler Steven Finn, the only England man yet to bat, said: "We had a very poor day, there is no hiding away from that.
"We have to make sure tomorrow is a very good day to make sure we stay in this game."
With the Ashes gone, Australia batsman Steve Smith, whose 143 put the tourists in the driving seat, hopes his side can give retiring skipper Michael Clarke a good send-off by winning this game.
"It is disappointing that we can't win the series but Michael said before this Test match that he wanted a lot of fight and character from us," said Smith.
"The way we batted and grinded out in the first innings showed that, and to have them 100-8, it's been a very good couple of days for us."
Meanwhile, Boycott also felt England were guilty of "believing their own publicity" after their limited-overs success against New Zealand earlier in the summer.
"After they played well in the one-dayers, they said we're going to play positive, attacking, aggressive cricket," he said.
"We want application, we want fight, we want some adaptability to the conditions."
Watch every episode of Pint-sized Ashes
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A man has been arrested after allegedly biting off a wedding guest's fingertip at a reception in Sydney.

The 42-year-old intruder walked into the private function at a pub on Saturday night and tried to steal handbags, the venue said.
When guests confronted him, a scuffle broke out and he severed a 47-year-old man's fingertip, according to police.
The intruder was charged by police with an assault offence. The victim's finger could not be saved, local media said.
The pub's licence holder, Fred Holovinsky, said experienced staff including a security guard were present at the time.
"But when somebody comes and creates a problem, you cannot control that," he said.
"(And) when you have got 50 or 60 people who take offence at somebody trying to steal a lady's handbag, how are you going to control that?"
The wounded man was taken to hospital for treatment and later released.
It was not the only violence on the night - police were later forced to break up a fight outside the pub.


Police hunting a "highly dangerous" convicted murderer who escaped custody in Liverpool have arrested four people.

Shaun Walmsley was sprung from custody by two armed men in February as he was getting into a cab with prison officers at Aintree University Hospital.
Merseyside Police have detained four people from Anfield - women aged 33 and 65, and men aged 38 and 66.
They are all being held on suspicion of assisting a person unlawfully at large and money laundering, police said.
After executing warrants in Anfield and Kinmel Bay in Conwy, officers also seized a "significant quantity of cash" and two vehicles, which will now be forensically examined.
Fourteen people have now been arrested in the investigation - the 10 people held previously have been released pending further inquiries.
Walmsley is one of four men serving life sentences for murdering Anthony Duffy in 2014.
Police have offered Â£20,000 of Walmsley's own money - seized by officers following his conviction - as a reward for information leading to his capture.
Detectives are appealing for information but have advised people not to approach Walmsley, who they describe as "highly dangerous".


Clydesdale Bank has announced the launch date for its second plastic bank note.

The bank revealed that its new £10 polymer note will enter circulation on 21 September.
It features Scottish poet Robert Burns on the front and views of Edinburgh's Old and New towns on the reverse.
The launch follows the introduction of Clydesdale Bank's £5 polymer note, which was released in September last year.
Like the £5 note, the £10 note is slightly smaller than its paper equivalent.
It features a shiny ink which changes colour as the note is moved and tilted.
Clydesdale Bank said the material would help the bank note stay cleaner than paper notes.
A tactile feature is also being introduced to help blind and partially sighted people.
David Duffy, chief executive of Clydesdale Bank owner CYBG, said: "I am proud to announce that our second polymer bank note will be available in our branches on 21 September 2017.
"The introduction of our £5 polymer bank note has led to a reduction in counterfeit levels and had a positive impact on the environment, and we believe the £10 version will have a same effect.
"More durable and more secure than normal paper notes, the move towards polymer is an important milestone in our history of innovation.
"We have been issuing banknotes since 1838 and it's just as vital as ever to ensure we are creating and developing currency that is fit for modern day use.
"It is also fitting that we are making this announcement on the 221st anniversary of the death of Robert Burns."
Other banks are also set to launch their polymer versions of £10 notes.
Bank of Scotland's new £10 note will enter circulation in the autumn.
Its front will continue to feature Scottish novelist and poet Sir Walter Scott alongside The Mound in Edinburgh.
RBS is also preparing to release its new £10 note, featuring scientist Mary Somerville.
And this week, Bank of England governor Mark Carney unveiled the bank's new plastic £10 note, which is due to be issued on 14 September.
It features a portrait of Jane Austen on the 200th anniversary of the author's death.


Bangladesh has banned an Islamist militant group accused of attacking and killing three secular bloggers, the interior ministry has said.

Its move to outlaw the Ansarullah Bangla Team (ABT) comes after police called for the group to be banned.
All three bloggers were hacked to death with sharp weapons earlier this year.
The attacks have led to big protests from activists who have accused the authorities of failing to protect critics of religious bigotry.
Police said last week that preliminary investigations implicated the the ABT in the three bloggers' murders.
They pointed to the similarities in the way all three bloggers were killed.
In each case, the attackers carried out their assaults on a busy street.
Death threats to secular bloggers are on the rise in Bangladesh. A few years back, hard-line Islamists demanded a blasphemy law to stop bloggers they perceived as being anti-Islamic from writing about Islam.
The first blogger to be killed - in February - was Bangladeshi-born US citizen Avijit Roy, who was hacked to death in the capital, Dhaka.
In March, another blogger, Washiqur Rahman, was also hacked to death in Dhaka.
Bangladesh is officially a secular country but more than 90% of its 160 million population are Muslim.
The ABT is the sixth Islamist militant group to be banned.


Marlon Samuels should keep having fun at England's expense, says West Indies bowling coach Sir Curtly Ambrose.

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Samuels continued his ongoing battle with Ben Stokes by saluting the England all-rounder after he was dismissed for eight on day three of the second Test.
As Stokes walked off he passed Samuels, who clutched his hat to his chest and raised his right hand to his temple.
"There's nothing wrong with a little bantering," said Ambrose. "This is international cricket."
Samuels said attempts by Stokes to goad him acted as motivation as he scored 103 in his side's innings of 299 on Wednesday.
And former England captain Michael Vaughan, commentating for BBC's Test Match Special, praised Samuels for his response.
"I think that's the greatest thing I've seen in Test cricket for a long time," said Vaughan.
"I hope he doesn't get any kind of fine. I thought that was brilliant banter."
Ambrose, who took 405 Test wickets in 98 appearances for West Indies, added a word of caution.
"As long as it doesn't go over the top, I'm fine with it," he said.
"I think it's more friendly than anything else. He gave a salute. Is that a sign of respect? I don't know but I'm hoping so.
"We always make sure that we tell the guys to keep it clean, keep it within a certain range and don't go over the top."
Joe Root dominated the third day's play, hitting an unbeaten 118 to put England firmly in control.
The tourists finished on 373-6, 74 runs ahead of the home side's first-innings total.
Samuels took the wicket of Gary Ballance, bowling the number three after he had made 77.
Download the Test Match Special podcast on the day's play.


Electronics giant LG has launched its first curved smartphone called the G-Flex.

Despite its name the G-Flex does not bend, but has a display which is curved from top to bottom.
LG says the curve helps the phone follow the shape of your face, putting the microphone closer to your mouth.
"Curved smartphones are a bit of a gimmick at the moment," said Newsbeat technology reporter Jonathan Blake.
He told Newsround: "They could be more comfortable to hold and companies claim the curved screen makes watching video more impressive."
"But apart from that the phones are very similar to other smartphones."
Tech rival Samsung revealed its own curved smartphone on 9 October. It wakes up from sleep mode when you rock it forwards.
But both smartphones are only going on sale in South Korea for the time being.
Jonathan said: "Technology companies need to keep up interest in their products and curved smartphones attract a lot of attention."
"But the fact they're only available in one country at the moment suggests the companies making them are not convinced they will take off."


(Close): US stocks fell sharply after China's surprise devaluation of the yuan, sending the currency to a three-year low against the dollar.

The move hit US companies exposed China and heightened worries about the health of the world's second largest economy.
Commodity prices also fell in reaction to the strengthening of the dollar.
The Dow Jones fell 212.33 points, or 1.21%, to 17,402.8, and the S&P 500 lost 20 points, or 0.96%, to 2,084. The Nasdaq end down 65, 1.27%, at 5,036.79.
Apple fell 5.2% and General Motors closed 3.48% lower on concerns that both companies' could be impacted by the devaluation. Alibaba was another casualty, down 3.9%.
Oil prices were down, with US crude falling 4% to $43.08 a barrel, its lowest since March 2009. That pushed down oil related stocks, with Exxon Mobil dropping 1.6%.
"Obviously this devaluation seems to suggest there's a lot of weakness, and we're in thinly-traded markets right now," said Eric Kuby, chief investment officer at North Star Investment Management.
"To a certain extent, the stocks that have propped up the market this year have slowly fallen out of favour, so I think that you're seeing a little bit of a flight to safety," he said.
Google provided one of the bright spots on the market, with its shares rising 4.1% after it announced a major restructuring, creating a new parent company called Alphabet Inc.
Under the rebranding, Google will retain its best-known businesses, such as search, apps, YouTube and Android.
Some of the newer entities, such as the investment and research divisions, the "smart-home" unit Nest, and the drone arm will be run under Alphabet.


Hundreds of thousands of people have taken part in protests across Brazil calling for the impeachment of President Dilma Rousseff.

Support for Ms Rousseff has fallen to single-digit figures in recent polls.
Many voters have accused her of failing to stamp out corruption and blame her for the economy's worst slump in 25 years.
Marchers took over Copacabana beach in Rio and also demonstrated outside congress in the capital Brasilia.
Many wore the yellow shirts of the Brazilian football team, and sang the national anthem, carrying banners saying "Dilma Out".
About 350,000 people took part in protests in Sao Paulo, police say.
Another 25,000 people took part in a demonstration in the capital, Brasilia.
The national day of action is the third major protest against Ms Rousseff and her left-wing Workers' Party this year. Hundreds of thousands took part in demonstrations in March and April.
"We want things to change and if the people don't go in the street that's impossible," said retired engineer Elino Alves de Moraes, who joined the march in Brasilia.
Ms Rousseff is less than a year into her second term as president.
There have also been demonstrations in recent months showing support for the embattled leader, with many claiming calls for her impeachment amount to a coup attempt.
People took to the streets to demand the impeachment of Dilma Rousseff, even though the perceived mood across the country in recent days has been one of reconciliation.  There's been an acceptance that to remove a democratically elected president might do more harm than good.
Overwhelmingly white and middle class, the protesters in Sao Paulo were having none of that argument. In generally jovial mood, they condemned the ruling Workers Party for its role in the corruption scandal surrounding Petrobras.
Ms Rousseff may have more to worry about further down the line, if Brazil's economy continues to decline after a decade of growth.
If inflation creeps above 10% and the economy goes into recession, that could alienate not only the privileged protesters of Sao Paulo, but her own working class base.
Read more from Wyre
Anti-government protesters say Ms Rouseff must have known about a corruption scandal in the state oil firm, Petrobras, as alleged bribery took place when she was head of the company.
She was exonerated in an investigation by the attorney general and denies involvement. However, several senior members of her government have been implicated.
Government austerity measures are also hugely unpopular with the electorate, correspondents say, as are rising unemployment and inflation rates.
A survey by the Brazilian company Datafolha showed support for Ms Rousseff's impeachment was strongest in the poorest areas, which backed her in the last election.


Security forces in Mexico have discovered an underground tunnel aimed at crossing into the United States.

The unfinished tunnel, in the border city of Tijuana, is believed to have been built by the Sinaloa cartel with the aim of smuggling drugs into the US.
Last month Joaquin "Shorty" Guzman, the leader of the Sinaloa cartel, escaped from a maximum security jail through a 1.5km-long (1 mile) tunnel.
Guzman, one of the world's most wanted drug dealers, is still on the run.
Officials from the federal prosecutor's office said the tunnel was 123m (404ft) long, but came just short of crossing the border.
The Mexican authorities uncovered the tunnel on 30 July, but they only allowed members of the media to access it on Sunday.
Members of the security forces said they had received an anonymous tip-off about a warehouse in Tijuana.
There, they found the unfinished tunnel, which had rails, lighting and ventilation.
It is the third such tunnel found in and around Tijuana this year.
No arrests were made.
The gang believed to be behind its construction, the Sinaloa cartel, are considered experts in the building of sophisticated tunnels.
Drug lord Joaquin Guzman, whose arrest in 2014 was seen as a major coup for President Enrique Pena Nieto, escaped through such a tunnel on 11 July.
It led from the shower of his cell in a maximum security jail to a building outside the prison's perimeter.
Despite a massive manhunt, Guzman's whereabouts remains unknown.
A number of prison staff, including the jail's director, have been arrested in connection with his escape.


Northern Ireland manager Michael O'Neill has insisted that he has had "no contact" with Norwich City over the Canaries position.

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On Tuesday, BBC Radio Norfolk reported that the Championship club had talked to O'Neill but he distanced himself from the role on Wednesday.
Norwich sacked Alex Neil in March, with Alan Irvine appointed interim manager.
Asked on Wednesday, if he had had any contact with the Canaries, formal or informal, O'Neill replied: "No."
"Nothing at all. There has been no contact between myself and Norwich City," O'Neill told BBC Sport Northern Ireland.
The Northern Ireland boss added:"Realistically, it's probably not what I would be looking for at this minute in time.
"I think the club are probably in the market for a head coach. I'm a manager. I've managed my country for the last five years and I intend to manage my country going forward.
"Any approach would have to be made through the Irish FA and it is my understanding that has not happened."
O'Neill added that the story "is just something which has obviously come from the media in England".
Irish FA chief executive Patrick Nelson added: "In keeping with our policy, we refuse to comment on speculation regarding our manager."
O'Neill, 47, led Northern Ireland to the last 16 at Euro 2016, having signed a new four-year deal in March 2016.
Tuesday's report stated that O'Neill had been one of several candidates being spoken to.
O'Neill's current deal with the Irish FA includes a release clause fee of £750,000 for Premier League clubs, although it is understood to be lower for Championship sides.
City are expected to appoint a new head coach soon after the final game of the season, against Queens Park Rangers on Sunday.


One in five children born as a twin in sub-Saharan Africa dies before their fifth birthday, according to new research in the Lancet.

The study is the first to analyse death rates among twins in the region.
The report suggests improvements in survival for twins is lagging far behind other children.
The death rate among single-born children aged under-five halved between 1995 and 2014. For twins, the rate came down by a third.
Giving birth to twins is riskier than delivering just one baby - no matter which country a mother delivers in.
There is an increased risk of early delivery, low birth weight and mothers suffering severe blood loss.
But researchers say these risks are "compounded" by higher overall birth rates and poor maternal and newborn care in sub-Saharan Africa, where many mothers give birth at home.
In Finland for example - which has some of the best maternity care in the world - researchers say for every 1,000 twins born, 11 die before their first birthday.
According to the study, the equivalent figure for sub-Saharan Africa is 137 per 1,000 twins who die before they turn one.
And 213 in 1,000 die before their fifth birthday.
Sub-Saharan Africa: 18 per 1,000 pregnancies
East Asia and Latin America: six to nine per 1,000 pregnancies
Europe, North America and the Middle East :  eight to 16 per 1,000 pregnancies
Source: Lancet
Researchers are calling for better health services to help these more vulnerable women and children.
Co-author, Prof Christiaan Monden from Oxford University, said: "So far, the poor fate of twins has gone largely unnoticed."
He said twin pregnancies needed to be detected earlier and mothers should give birth in a hospital with staff trained in twin deliveries.
This should be followed by continued monitoring in the first few days and even months of their lives.
But this is a big ask in some of the poorest countries with some of the weakest health systems in the world.
Families, particularly those living in remote areas, often do not have hospitals anywhere near where they live.
Many cannot afford the transport to get to the nearest maternity facility, let alone pay for the care they need.
Even if they could, facilities such as specialist twin delivery care are few-and-far-between in many developing countries.
Prof Monden added: "It is very easy to say mothers should just give birth in a nice hospital, but that is not a realistic option for many.
"What surprised us when we found the higher death rate among twins is we thought this must be well-known by big UN organisations and that they pay special attention to twins - but this is not the case."
Co-author, Dr Jeroen Smits, from Radboud University Nijmegen in the Netherlands, said: "Without special attention to this vulnerable group it will be very difficult to achieve the UN's sustainable development goal target of fewer than 12 per 1,000 neonatal deaths and fewer than 25 per 1,000 under-five deaths by 2030."
The report used data from 1.69 million children born in 30 sub-Saharan African countries between 1995 and 2014
It included more than 56,000 twins.
16,399 twins died before their fifth birthday.


A drama portraying the events surrounding the deaths of 144 people in a Welsh village will be aired to mark the 50th anniversary of the tragedy.

In 1966, a coal waste tip slid down a mountain above Aberfan, south Wales, onto the village school, killing 116 children and 28 adults.
The Green Hollow has been written by author Owen Sheers based on interviews with those involved.
The drama is part of a new season of BBC Wales-produced programming.
The hour-long programme, in the form of a poetry film, will feature high-profile Welsh actors including Michael Sheen, Jonathan Pryce, Sian Phillips and Eve Myles.
Owen Sheers said of the programme: "As well as remembering the circumstances and consequences of the disaster, it became equally important for me to create a portrait of what the village was like in 1966 before tip number seven collapsed on Pantglas School - a thriving, vibrant cultural and economic community - and also to paint a picture of the fortitude and optimism present in the village today."
The programme will be broadcast on the day of the anniversary, Friday 21 October on BBC One Wales and BBC Four.
Also making a return to both channels in October will be Ordinary Lies, the Newport-based drama set in a sports company starring Griff Rhys Jones and Kimberley Nixon.
A Doctor Who spin-off for young adults, Class, will be screened on BBC Three from 22 October, while the Ceredigion-set crime drama Hinterland, which is in its third series, will return in the new year to BBC One Wales and BBC Four starring Richard Harrington.
BBC Wales director Rhodri Talfan Davies said: "These four very special shows provide a glimpse into very different Welsh experiences - from the lives and passions of a Newport workforce to the brooding landscapes of west Wales.
"They showcase the brilliant production and acting talent Wales has to offer, and underline the BBC's commitment to improve the portrayal of Wales on the BBC's networks."


Lewis Hamilton put in a scintillating performance to take pole position for the Malaysian Grand Prix.

The world champion was 0.414 seconds quicker than Mercedes team-mate Nico Rosberg, with the Red Bulls of Max Verstappen and Daniel Ricciardo next.
Ferrari's Sebastian Vettel and Kimi Raikkonen continued the two-by-two in fifth and sixth places.
Hamilton has a great chance to recover some of his eight-point title-race deficit to Rosberg in Sunday's race.
The Briton was dominant throughout, with Rosberg only fifth after the first runs in final qualifying and having to rely on a last-gasp lap to vault up to the front row.
Hamilton looked fast in final practice and took that form into the start of qualifying as he topped all three sessions.
He was nearly 0.6secs up on Rosberg in second qualifying and then a massive 0.911secs clear after the first runs in Q3, on which Rosberg had a snap oversteer and ran wide off the track through the fast Turn Six.
Hamilton lost the championship lead to Rosberg following the German's victory in Singapore two weeks ago but has been driving this weekend as if intent on recovering it in one go.
Rosberg has moved into that position after winning the past three races to overturn what had been a 19-point advantage for Hamilton after the German Grand Prix in July.
Hamilton said: "It's been a difficult few weeks with Nico's wins but today the car felt fantastic. I really enjoyed the lap - but could have been faster."
Rosberg said: "Lewis' lap was very quick so it was always going to be difficult. I would have come close but I had a mistake in the last corner. Something just wasn't going right there.
"But anyway, second place - I've got to live with that now and, as we know from this year, second does not mean victory is not possible."
That is a reference to the difficulty with starts both Mercedes drivers have had intermittently throughout this season.
Although Mercedes dominated qualifying, there is the possibility they will face a challenge for the victory from both Red Bull and Ferrari.
Verstappen, who out-qualified Ricciardo for only the third time in their 12 races as team-mates, was the fastest driver in the race-simulation runs in Friday practice, with Mercedes and Ferrari closely matched just behind.
Hamilton said: "The [newly resurfaced] track is generally better, a lot smoother and works better with the tyres. It will be a difficult race because they were looking strong on the long runs, but I think we will be pretty strong too."
Behind the top three teams, Force India's Sergio Perez was seventh as it emerged he has, after weeks of speculation, apparently completed the deal that will keep him at the team in 2017.
His team-mate Nico Hulkenberg was eighth, ahead of Jenson Button's McLaren and Felipe Massa's Williams.
Button's team-mate Fernando Alonso was last after deliberately doing only one lap good enough to get him within the 107% qualifying rule, as was the plan as a result of an engine penalty that meant he was going to be at the back of the grid.
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Renault's Jolyon Palmer was disappointed to be 19th, 0.3secs slower than team-mate Kevin Magnussen as he was knocked out in Q1 and five places behind him on the grid.
Palmer: "It was crap, I drove terribly. I made a wrong choice on the set-up. Terrible."
Malaysian Grand Prix qualifying results
Malaysian Grand Prix coverage details


The Lib Dems say they would refuse to join a coalition with a party that did not agree to raise public sector pay.

Nick Clegg will say his party's policy, announced last month, would be a "red line" in post-election negotiations.
The parties are trying to rally support on the final weekend of campaigning.
David Cameron will urge voters to "stop and think" about the "historic choice" facing them on Thursday, while Labour will attempt to put pressure on the other parties over tuition fees.
The two largest parties appear to be neck and neck according to most of the opinion polls carried out for the Sunday newspapers.
This suggests a hung parliament is likely, and the Lib Dems have been setting out their "red lines" - with public sector pay joining education spending, a £12,500 personal allowance, £8bn for the NHS and an emergency "stability budget".
Mr Clegg has already said his opposition to an EU referendum - as proposed by the Conservatives and UKIP - will not be a red line.
He has also said he would talk to the largest party first if there is a hung parliament, and that he would not join a government that relied on support from the SNP or UKIP.
His final policy demand involves public sector pay rising with inflation for two years from 2016, and then by more than inflation once the deficit has been dealt with.
What are the top issues for each political party at the 2015 general election?
Policy guide: Where the parties stand
Public sector pay was frozen for the first two years of the coalition government, followed by 1% rises. Schools have been given the power to award top-performing teachers a rise of up to 2%.
The Conservatives plan to continue "restraining" public sector pay, which was increased by up to 1% in March.
Labour's manifesto says any decisions on public sector pay in the next Parliament must "prioritise those on lower incomes", be evidence based and respect pay review body recommendations.
Mr Clegg will say it is time to offer public servants "some light at the end of the tunnel".
He will add: "Liberal Democrats will not enter a coalition with a party not prepared to back pay rises for people working in the public sector.
"They have paid more than their fair share, and now enough is enough."
His party has sought to portray itself as the centre-ground "anchor" of a future coalition.
Mr Clegg also told the Independent on Sunday he would not allow his party to "split" as a result of pressure to go into coalition, saying this would be a "disaster".
Mr Cameron, meanwhile, will urge people not to vote tactically for the Lib Dems or back UKIP if they want him to remain in Downing Street.
He will say a vote for UKIP would let in Labour, which would herald a "sharp turn to the left" and that the Lib Dems would also be willing to side with Ed Miliband's party.
"As you spend time with your family and friends, I'd urge all voters to take a moment and stop and think about the decision they have to make in just four days' time," he will say.
"It's no exaggeration to say Britain will be making an historic choice."
Labour, meanwhile, will claim Conservative plans for spending cuts suggest a rise in tuition fees up to £11,500 a year.
The party said this was based on a £1.5bn cut to the higher education budget by 2018-19.


A rocket launched by Islamic State militants at American troops based in Iraq did contain a mustard agent, the US military has confirmed.

No-one was hurt in Tuesday's attack on the Qayyarah air base near the IS stronghold of Mosul.
Marine Gen Joseph Dunford, chairman of US joint chiefs of staff, said the group's capability to deliver chemical weapons was rudimentary.
But the attack, he added, was a "concerning development".
IS has long been suspected of making and using crude chemical weapons in Iraq and Syria, where it also controls territory.
Gen Dunford told the US Senate armed services committee on Thursday that the rocket had contained a "sulphur-mustard blister agent".
Mustard agent in sufficient quantities can maim or kill by damaging skin, eyes and airways.
Mosul, Iraq's second largest city, has been under IS control for the past two years and the battle to retake it is expected to begin in the coming weeks.
US troops are providing assistance to local forces as they prepare for the offensive.


Tennis star Andy Murray says he and his wife, Kim Sears, are "very happy" to be expecting their second child.

The couple, who married in 2015, already have a one-year-old daughter, Sophia.
The news come as the 30-year-old prepares for his opening match at Wimbledon on Monday as defending champion.
He told reporters: "We're both obviously very happy and looking forward to it."
The world number one also confirmed he was fit to play following his recent hip injury, saying: "It's felt much better the last few days."
Asked if the news of the baby on the way would put any extra pressure on him going into the tournament, he said: "No, I wouldn't have thought so."
He said family life was "certainly not a distraction in the slightest".
Regarding his wife, Murray added: "She'll be coming to Wimbledon. And we found out a while ago. But I'm not interested in discussing the dates of that in here."
Andy and Kim were married in Murray's home town of Dunblane in April 2015 and their daughter Sophia was born in February 2016.
The world number one has spoken about how his family is the most important thing in his life and he has said becoming a husband and father has helped his tennis.
Murray said he was feeling "good" after practising three times on Friday as he recovers from a hip injury which saw him pull out of his final warm-up match ahead of the tournament.
He will face Kazakhstan's Alexander Bublik, who is world number 134, on Centre Court at 13:00 BST on Monday.


Attempts to cut the amount people smoke are being hit by a black market trade in millions of illegal cigarettes, council bosses have warned.

The Local Government Association (LGA) said such products posed a fire risk, hurt legitimate businesses and cost the UK about Â£3bn a year in unpaid duty.
In some cases these cigarettes contained human excrement, dead flies and asbestos, the LGA added.
Councils have carried out a series of raids to target the illicit trade.
Hundreds of thousands of illegal cigarettes have been seized in Wolverhampton, Bristol and Nottingham, and sniffer dogs were used to search 12 locations in Birmingham.
Southwark, Bexley, Bromley, Greenwich, Lambeth and Lewisham councils in south London have joined forces to tackle the trade in the estimated 114 million illicit cigarettes sold across their areas each year.
Trading standards officers have found fake cigarettes hidden inside vacuum cleaners, under floorboards and in toilet cisterns.
Many feature much higher levels of toxic ingredients such as tar, nicotine, carbon monoxide, lead, cadmium and arsenic than normal cigarettes.
They also may not have safety precautions that ensure genuine cigarettes put themselves out if they are not smoked, thus reducing the risk of accidental fires.
Joanna Spicer, vice-chairwoman of the LGA's safer and stronger communities board, said: "Counterfeit tobacco being sold cheaply through the black market by rogue traders is hampering council efforts to reduce smoking.
"This illicit trade is also funding organised criminal gangs, damaging the livelihoods of honest businesses and costing taxpayers billions of pounds a year.
"People buying cheap cigarettes might think they are getting a great deal - but the truth is that they're not. If they knew what they might contain, they might think twice about buying them.
"Council prosecutions should serve as a strong warning to any shopkeeper thinking of stocking their shelves with illegal tobacco and not thinking twice about selling them cheaply to children and others."


AC Milan fought back from 2-0 down at half-time to secure a point at Torino and go fifth in the Serie A table.

Andrea Belotti's 14th Italian top-flight goal of the season and Marco Benassi's effort put Torino in command.
Milan's 17-year-old keeper Gianluigi Donnarumma saved Adem Ljajic's penalty to prevent the hosts going 3-0 up.
Andrea Bertolacci reduced the deficit for the visitors - who finished the game with 10 men - before Carlos Bacca's penalty completed the comeback.
Belotti brushed the Milan post in the closing stages after Joe Hart had earlier produced a finger-tip save to deny Suso in what was a thrilling match
Milan, who had Alessio Romagnoli sent off in the 89th minute after a second yellow card, move one point clear of rivals Inter and eight behind leaders Juventus.
Torino, knocked out of the Coppa Italia by Monday's opponents last week, are 15 points off the top.
Match ends, Torino 2, Milan 2.
Second Half ends, Torino 2, Milan 2.
Attempt missed. Suso (Milan) left footed shot from outside the box is high and wide to the left. Assisted by Juraj Kucka.
Foul by Carlos Bacca (Milan).
Luca Rossettini (Torino) wins a free kick on the right wing.
Second yellow card to Alessio Romagnoli (Milan) for a bad foul.
Foul by Alessio Romagnoli (Milan).
Andrea Belotti (Torino) wins a free kick in the attacking half.
Substitution, Milan. Leonel Vangioni replaces Davide Calabria.
Corner,  Torino. Conceded by Gianluigi Donnarumma.
Attempt saved. Adem Ljajic (Torino) right footed shot from the right side of the box is saved in the top centre of the goal. Assisted by Iago Falque.
Substitution, Milan. M'Baye Niang replaces Giacomo Bonaventura.
Attempt missed. Davide Calabria (Milan) right footed shot from the left side of the box is close, but misses to the left. Assisted by Mario Pasalic.
Substitution, Torino. Daniele Baselli replaces Marco Benassi.
Attempt blocked. Juraj Kucka (Milan) right footed shot from outside the box is blocked. Assisted by Giacomo Bonaventura.
Attempt saved. Carlos Bacca (Milan) right footed shot from the left side of the six yard box is saved in the bottom right corner. Assisted by Giacomo Bonaventura with a cross.
Iago Falque (Torino) is shown the yellow card for a bad foul.
Giacomo Bonaventura (Milan) wins a free kick in the attacking half.
Foul by Iago Falque (Torino).
Foul by Carlos Bacca (Milan).
Emiliano Moretti (Torino) wins a free kick in the defensive half.
Attempt missed. Mario Pasalic (Milan) right footed shot from the left side of the box is too high. Assisted by Suso.
Attempt missed. Andrea Belotti (Torino) right footed shot from the centre of the box is close, but misses to the right. Assisted by Marco Benassi with a cross.
Substitution, Milan. Juraj Kucka replaces Andrea Bertolacci.
Attempt missed. Juan Iturbe (Torino) left footed shot from outside the box misses to the right.
Foul by Suso (Milan).
Juan Iturbe (Torino) wins a free kick in the defensive half.
Hand ball by Sasa Lukic (Torino).
Attempt missed. Adem Ljajic (Torino) right footed shot from outside the box is close, but misses to the left. Assisted by Sasa Lukic.
Substitution, Torino. Sasa Lukic replaces Mirko Valdifiori because of an injury.
Attempt blocked. Juan Iturbe (Torino) left footed shot from outside the box is blocked. Assisted by Mirko Valdifiori.
Corner,  Torino. Conceded by Ignazio Abate.
Delay over. They are ready to continue.
Delay in match Mirko Valdifiori (Torino) because of an injury.
Attempt missed. Marco Benassi (Torino) right footed shot from outside the box misses to the left. Assisted by Andrea Belotti with a headed pass following a corner.
Corner,  Torino. Conceded by Alessio Romagnoli.
Substitution, Torino. Juan Iturbe replaces Joel Obi.
Goal!  Torino 2, Milan 2. Carlos Bacca (Milan) converts the penalty with a right footed shot to the bottom right corner.
Luca Rossettini (Torino) is shown the yellow card for a bad foul.
Penalty Milan. Gabriel Paletta draws a foul in the penalty area.


Leaving the EU poses a "key risk" to British science, a group of 13 Nobel prize-winning scientists have warned.

The group, which includes Peter Higgs, who predicted the existence of the Higgs boson particle, and geneticist Sir Paul Nurse, say losing EU funding would put UK research "in jeopardy".
"Inside the EU, Britain helps steer the biggest scientific powerhouse in the world", the group claim.
Vote Leave said it was a "myth" that funding came from Brussels.
In a letter to the Daily Telegraph the group said science should be "front and centre in the EU debate" as it was a key driver in health, innovation and economic growth.
"The EU contains a critical mass of expertise, with more than one in five of the world's researchers moving freely within its boundaries.
"EU decisions about scientific policy, funding and regulatory frameworks affect science the world over, and are influenced by British scientists. On the inside, Britain has access to people and funding and wields global scientific influence, far greater than we have alone."
How education and scientific, technical and medical research relate to membership.
The signatories also include Sir Martin Evans, the chancellor of Cardiff University who was awarded for his work into stem cells, and Sir Andre Geim who won a Nobel prize for groundbreaking work on graphene, a material expected to revolutionise manufacturing.
The letter comes as MPs urged ministers to draw up contingency plans to protect the UK's science sector in the event of a vote to leave the EU on 23 June.
The Commons Science and Technology Committee said the UK benefited "significantly" from access to EU research budgets and would have to seek other sources for funding if it was withdrawn.
It highlighted the "cautionary example" of Switzerland, which was denied access to science funding programmes when the EU imposed sanctions in response to a vote to curtail the freedom of movement.
Committee chairman Nicola Blackwood said: "In light of this, the government must conduct a risk analysis of the impact that a vote to leave would have on science funding and international collaboration."
The committee - which includes supporters of both Leave and Remain - did not come down on either side in the debate, noting that there were both benefits and costs to the UK science sector from EU membership.
It comes after Prof Stephen Hawking said Brexit would be a "disaster for UK science".
But a group of researchers arguing the case for an EU exit disagreed saying Britain would be no worse off on the outside.
Prof Angus Dalgleish from the University of London and a spokesman for "Scientists For Britain" said: "We are standing up against what is a very large body of people who feel that if we leave the EU it will be a disaster for funding and collaboration - and we completely refute that," he said.
A poll of nearly 2,000 researchers living in the EU conducted by Nature in March found 83% were in favour of Britain staying in.
A spokesman for Vote Leave said: "The biggest myth in this campaign is that money that funds our universities, our farmers comes from a magical money tree in Brussels.
"There is no such thing as EU money - it is all paid for by British taxpayers as part of the three hundred and fifty million pounds sent to Brussels every week."
Meanwhile some of Britain's largest developers have also urged voters to back Remain.
House building companies and housing associations, including Barratt Developments and Wates Group, say a vote for Brexit would cause economic uncertainty and damage investment which would make the housing crisis worse.
"What any developer requires is confidence and continued support from their financial investors - and those investors need certainty over wider market conditions," the developers wrote in an open letter.
"Leaving the EU would also have an impact on the UK's housing supply chain companies, which employ millions of people across the UK. This could disrupt the production and import of the supplies needed for building such as bricks and blocks. This will further delay and add costs on Britain's house builders."
The Vote Leave campaign said the scale of immigration from the EU was the cause of much of the pressure on the housing market.


The Syrian Prime Minister Wail al-Halqi has described the ousting of rebels from Qusair as "a strategic turning point".

Similar claims were made in February last year when government forces finally overran the rebel-held quarter of Baba Amr in Homs.
That turned out not to be the seminal victory the regime had hoped for, although, as with Qusair, both sides had invested the battle there with huge political and symbolic significance.
The fall of Qusair town had become more or less a formality after government forces and their Hezbollah allies won control of most of the surrounding countryside.
In the end, rebel fighters recognised their situation as untenable and withdrew on Tuesday night, apparently under an informal understanding that they would be allowed safe passage. That enabled army troops and Hezbollah to advance into the town unopposed the following morning.
Whether the government victory at Qusair will prove to be a real turning point will depend on the wider ebb and flow of the struggle for control of the country.
But in immediate terms, it is clearly a major blow to the rebels, denying them easy use of an important supply route from friendly, Sunni-populated enclaves in north-east Lebanon to Homs and central Syria.
From Hezbollah's point of view, it gives the Shia movement an easier connection between Lebanon's eastern Bekaa Valley, where Hezbollah holds sway, and the major Syrian cities, as well as the Alawite coastal heartland to the north-west, which could prove vital if Syria eventually heads towards fragmentation.
The move at Qusair was part of a broader regime campaign to sever cross-border supply routes that has scored some success in the south and north as well.
Combined with an aggressive campaign to regain control of the suburbs around Damascus, all this has meant that the threat of a rebel assault on the centre of the capital, which seemed imminent towards the end of last year, has been staved off, at least for the time being.
But diplomats believe these gains could not have been made without help from Hezbollah, not just at Qusair but also around Damascus, where Iraqi Shia militias have also been playing a role.
The assumption is that Hezbollah will continue its spearheading role in other areas, perhaps Homs and Aleppo.
But its resources and manpower are not infinite, and unless there is a wholesale collapse of rebel morale and capabilities, it is hard to imagine regime and allied forces rapidly reconquering the whole country, as government officials have pledged.
But the Qusair affair has highlighted not just the fragmented nature of the rebel fighters on the ground, but also the total disarray of the Istanbul-based political opposition.
While that contrasts with the regime's singleness of purpose, there is a similarly glaring discrepancy between the focused commitment Damascus has been able to count on from its key allies, Russia, Iran and Hezbollah, and the discordant, hesitant and ineffective backing provided to the opposition by its motley array of regional and Western supporters.
If an international peace conference does indeed emerge from the American and Russian proposal, Qusair leaves the opposition in disastrous shape in terms of confronting a tough, cohesive regime team.


Police have regained control of a prison on the outskirts of Melbourne following a major riot.

Staff and visitors were evacuated from a remand centre in Ravenhall after clashes involving hundreds of inmates began at midday on Tuesday.
Heavily armed police stormed the prison in the early hours of the morning, according to the Victorian government.
The Corrections Department said the riot may have started because of a smoking ban in state prisons.
Several prisoners were hurt in the riot and were treated by medical staff, and two staff members suffered minor injuries, said prison authorities.
The riot, in which hundreds of prisoners lit fires, broke walls and smashed windows, started not long before a smoking ban was to be introduced in all Victorian correctional facilities.
About 84% of Victorian prisoners are smokers, according to government figures.
The government said it was introducing the ban to improve the health of prison staff and inmates.
Corrections Victoria said the operation to end the riot was difficult and conducted under the cover of darkness to protect prison staff.
Victoria's Minister for Corrections, Wade Noonan, said  "a thorough investigation" would be undertaken into what caused the riot and how authorities responded to it.


Come and meet those dancing feet, they said to the Duchess of Cambridge - and meet them she did.

The result was a right royal launch for the latest West End production of 42nd Street, with Kate as guest of honour.
Hollywood star Morgan Freeman, DJ Sara Cox and Dame Esther Rantzen were also among the audience at London's Theatre Royal Drury Lane on Tuesday.
Based on the 1933 film, the show tells of a young performer in Depression-era New York who gets a shot at stardom.
Dressed in a maroon Marchesa gown, the Duchess attended in her role as Royal Patron of East Anglia's Children's Hospices.
She left with a golden pair of tap shoes, presented to her on stage after the curtain call by Mark Bramble, the show's director and co-author.
Tap is in abundance during the musical itself, which dramatises the painstaking coming-together of a Broadway stage spectacular.
Scottish-born singer Sheena Easton heads its cast, making her West End debut as a temperamental star whose indisposition allows an unknown chorine, played by Clare Halse, to take centre stage.
According to co-producer Michael Grade, the musical - which features such familiar songs as Lullaby of Broadway, Keep Young and Beautiful and We're In The Money - is "the right show at the right time".
"I think the public are ready for just some pure entertainment," said the former BBC chairman. "You're guaranteed to come out feeling better than when you went in."
"In times of trouble we look for things that bring us joy," agreed the choreographer Arlene Phillips. "It's a great story, a big, old-fashioned musical, and it just gets right inside you."
What did the critics make of it though? Here's a breakdown of what the Telegraph, the Mail, the Mirror, The Times and The Guardian have been saying.
The West End opening of 42nd Street comes only a few weeks after that of An American in Paris, another old-school mix of classic songs, tireless hoofing and glamorous spectacle.
London's theatrical nostalgia boom will continue next month when the Open Air theatre in Regent's Park launches its summer revival of On the Town.
Follow us on Facebook, on Twitter @BBCNewsEnts, or on Instagram at bbcnewsents. If you have a story suggestion email entertainment.news@bbc.co.uk.


Aston Villa do not the fear the consequences of relegation from the Premier League and will come back "on a stronger footing" if they do go down, says new chairman Steven Hollis.

Villa are bottom of the table, eight points from safety, with 17 games left.
Hollis told BBC Sport the club needed "shaking up" but insisted that spending money on players was not the solution.
He will work with chief executive Tom Fox, who described the club's current football setup as "broken".
Villa owner Randy Lerner has described Hollis as someone with a "proven track record for getting into the thick of troubled organisations",
Villa's 1-0 home win over Crystal Palace on Tuesday was only their second league win of the season and their first since the opening day, but they are still bottom of the league, eight points behind Swansea, who are one place above the relegation zone.
There is added pressure to stay in the Premier League with clubs set to benefit from the start of a new £5.1bn three-year television rights deal from next season.
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However, West Midlands businessman Hollis, who was appointed on Thursday, said: "If we unfortunately have to go through a relegation phase, we have no fear of that.
"Randy Lerner is committed and is going to support the board and executive team to take the actions we need to put us in the best possible position so we can come up as quickly as possible.
"This club will be here and we will be on a stronger footing."
Fox added: "Where we are this season is not where any of us want to be. Randy feels that very deeply. He knows how difficult it is for the fans facing another relegation battle. It is difficult for the players and everyone in the organisation.
"He is not happy but we do not live in fear of what might happen. The thing that makes Randy feel good about the future of the club is that we are putting these kind of processes in place and he has an executive management team that he trusts.
"He believes in the manager he has got. He is positive right now, despite where we are."
United States-based Lerner, who bought Villa in 2006 and announced at the end of last season he was looking to sell the club, has described Hollis as someone with a "proven track record for getting into the thick of troubled organisations, working with embattled executives and getting results".
"Randy was very clear when I met him that there is some heavy lifting that needs doing at this club to address the structural flaws it has experienced over the last five years," said Hollis. "Randy wanted the work to be done and wanted it done quickly, hence I am here.
"There is a big job to be done. And as chairman I really do want to bring back the confidence to this club, both on the playing side and non-playing side, so we can feel good about what we are doing.
"Time will tell if I am right or not. But I have spent six weeks looking at this and I genuinely believe this needs an overhaul and it needs some solid business principals inputting into it.
"We are going to have to look at how we can shake this club up so we can put it on the correct footing where we can have a position where we can command in the Premier League. That will take some time."
In the early years of Lerner's ownership, Villa established themselves as a top-six Premier League team under the management of Martin O'Neill.
For the last five seasons, though, they have battled against relegation and current boss Remi Garde is their fifth manager in that time.
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"There is something not right with our football set-up at Bodymoor Heath," admitted Fox. "When we talk about it, we say that it is fundamentally broken and has been for a while.
"The results speak for themselves. When a great club like this, with its history and heritage and success it has had in the past, finds itself in a relegation battle for five seasons in a row, despite spending money to bring players in and changing managers, you have to ask yourself 'what is fundamentally wrong?'
"The principles Steve talks about are the ones we need to bring to our football set-up so that when we got to our board and ask them to spend money on acquiring players or coaches, we have a good sense for how that investment is going to pay off for the owner and how it is ultimately going to deliver results on the pitch."
Hollis added: "Randy spent a lot of money last summer and we are not seeing the result of that. This is about hard work, commitment and a focus on continuous improvement."
In the summer, midfielder Fabian Delph and striker Christian Benteke were sold for sizable fees, much of which was reinvested in signing 13 players, many of whom have failed to perform for the club so far this season.
Garde's predecessor, Tim Sherwood, has revealed that the signing of these players was conducted via a "transfer committee" at the club, with Lerner having final say.
But Fox defended the club's recruitment process and said they are looking at ways of improving the squad in January.
"We are taking a deep look at the squad and taking a lot of time with Remi to try and understand what our needs are and the best ways to address those," he said.
"In terms of the process we ran over the summer and will run this January, you can call it what you want - some have called it a committee - but we don't buy or sell players any differently to any other top or successful club.
"If Remi is not happy with a player who has been suggested, he says no. We never end up with a list of players we are targeting that isn't an approved list from the manager."


Drivers' concerns about the defensive tactics of Red Bull's Max Verstappen have led to Formula 1 outlawing moving under braking.

The Dutchman has employed this tactic as a trademark in battles with rivals but many other drivers have complained that it is extremely dangerous.
Race director Charlie Whiting was told at the US Grand Prix that there would be a big accident if he did not act.
Whiting has issued a ruling saying such moves will be considered illegal.
"It is like it is," Verstappen said about the rule.
"It's good to make it clearer what's allowed and what's not.
"I'm just going to race and then we will see how it is going to be defending and how it will affect the racing."
This is likely to become known as the "Verstappen rule" after a series of controversies involving the 19-year-old this year.
These have included his battles with Ferrari driver Kimi Raikkonen at the Hungarian and Belgian Grands Prix, and with Mercedes' Lewis Hamilton at the last race in Japan.
Mercedes lodged a protest against Verstappen's driving in Suzuka, which resulted in Hamilton taking avoiding action and going up the escape road at the chicane, but subsequently withdrew it.
The drivers' concerns about Verstappen's driving focus on two main areas: moving - or changing line - under braking; and what is called "wait-and-move".
The second is when a driver defending his position waits to see which side the driver behind will attack on and only moves to defend after he has done so.
Many drivers consider both situations to be dangerous and even dirty because they are already on the limit during braking so cannot brake harder and avoiding the car in front is difficult.
Whiting has been confronted about the issue a number of times this season. His initial response was that Verstappen was driving on the edge but just within the bounds of acceptability.
Verstappen has twice in recent races been taken aside by Whiting and warned to be careful about how he drives in such situations.
But after repeated complaints from the drivers, Whiting has been persuaded that he needs to take action.
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His new ruling is predicated on article 27.5 of the sporting regulations which states that "no car may be driven… in a manner which could be potentially dangerous to other drivers…" and article 27.8, which prohibits any manoeuvre "liable to hinder other drivers, such as… any abnormal change of direction".
The drivers and teams have been reminded of article 27.6, which says: "More than one change of direction to defend a position is not permitted. Any driver moving back towards the racing line, having earlier defended his position off-line, should leave at least one car width between his own car and the edge of the track on the approach to the corner."
Four-time world champion Sebastian Vettel, a director of the Grand Prix Drivers' Association, said: "It is very simple. The day I joined F1 it was clear and it was a sort of unwritten law, and in recent times we have had situations and got away with it.
"So for sure then the message is that everyone is starting to do it. It is the wrong thing because, as we spoke about yesterday, we are just waiting for something to happen. Therefore I think it is a good action."
United States Grand Prix coverage details


A woman has been charged with a causing the death of a biker who was killed on the A12 in Suffolk.

Adrian Klein, 39, from Yoxford, was riding his Suzuki at Kelsale-cum-Carlton when it was involved in a collision with a car on 26 March.
Sharon Nobinger, 44, of Mayflower Avenue, Saxmundham, has been charged with causing death by careless or inconsiderate driving.
She is due before magistrates in Lowestoft on 28 October.
Suffolk Police were called to the A12 just after 19:00 GMT on the day of the crash.
Two other people from the Saxmundham area who were arrested were released without charge.


Police have named a man who fell into the River Forth from the Clackmannanshire Bridge after officers tried to stop his van.

Dean Wood, 21, from Sauchie, has been missing since the incident in the early hours of Friday.
Police said they were continuing to search in and around the river in an effort to trace him.
Ch Insp Irene Ralston said: "We are supporting his family who are extremely anxious to hear news of Dean.
"I would urge anyone who has any information that can assist to contact police immediately."
Dean is described as white, 5ft 7in tall, of slim build with short brown hair. He was wearing a red hooded top, blue jeans and brown boots.
Officers are keen to speak to anyone who may have had contact with Mr Wood during Thursday evening, and anyone who may have seen a Ford Transit van before the incident.
The incident occurred after officers in an armed response vehicle spotted a blue Transit van that was being driven with three wheels on the Clackmannanshire Bridge.
When they signalled to the driver to stop, he crashed the van into a barrier on the bridge.
He then got out and climbed over the bridge's safety railings before entering the River Forth.
In a statement, Mr Wood's family said: "We are all totally devastated by the events of Friday morning and along with friends and relatives are hoping and praying for news of Dean.
"Dean is a likeable good natured young man with a zest for life and a good sense of humour.
"We are thankful and reassured by the efforts of everyone involved in the search for Dean and the support we have received at this difficult time."


A sixth of the way to Mars, to the Moon and back three times, around 250 circuits of the equator, or, to put it another wayâ€¦ an awfully long way.
That is roughly how far narrow gauge steam locomotive Palmerston has travelled during her 153 years on the Ffestiniog Railway.
But now she is getting a well-earned week's rest, as she returns to London for the first time since she was built, to go on display in the ticket office of King's Cross Station.
The visit is to mark the launch of Big Train Meets Little Train, a UK government-funded free guide to Welsh narrow gauge railways and how to visit them by rail.
Chris Parry of the Ffestiniog Railway explained: "Palmerston was built at George England's Hatcham Iron Works in East London and was completed in March 1864.
"She was named after Viscount Palmerston, Liberal prime minister and chairman of the Welsh Slate, Copper & Lead Mining Company's quarry at Blaenau Ffestiniog.
"The George England engines are the oldest surviving narrow gauge locomotives in the world. Remarkably, after more than 150 years, four of the six built still survive, two of them in regular use and a third being restored for a return to service later this year."
Palmerston saw extensive use on both the Ffestiniog and Welsh Highland Railways until withdrawal from service in 1937.
Despite being deemed "beyond repair", she was the subject of a long restoration and eventually re-entered service on the railway in 1993.
Her sister engines were Prince and Princess - named to mark the marriage of the Prince of Wales, the future Edward VII, to Princess Alexandra of Denmark - and Mountaineer, reflecting the rugged terrain over which the railway operates.
The world's oldest large-scale narrow gauge system, The Ffestiniog and its sister railway the Welsh Highland form the longest heritage line in the UK - stretching 40 miles coast to coast from Caernarfon to Porthmadog and Blaenau Ffestiniog - and carrying nearly 400,000 passengers each year.
The little engines rack up about 63,500 miles annually, meaning that - allowing for her 56-year-enforced layoff - Palmerston has somewhere in the region of six million miles on the clock.
While they may look quaint nowadays, when they went into service in 1864 they were the cutting edge of technology.
The Ffestiniog was the first railway in the world to adopt and make regular use of steam locomotives on a very narrow gauge, on a public railway and over a significant distance.
They demonstrated that steam technology that had evolved on the main lines from 1829 onwards could be applied to railways built on a much smaller scale and at much lower cost.
Attracting engineers from around the globe, The Ffestiniog proved the blueprint for narrow gauge railways the world over, including France, India, the USA, Hungary, South Africa, Namibia, Venezuela, New Guinea and Morocco, as well as the railways built to serve the trenches of the First World War.
Throughout her visit until 25 February, staff and volunteers from The Ffestiniog will be on hand at King's Cross to answer enthusiasts' questions.


Lincoln City midfielder Alex Woodyard has signed a one-year contract extension, keeping him at the club until the end of the 2018-19 season.

Woodyard, 24, joined the Imps last summer having also played for boss Danny Cowley at Braintree.
He made 52 appearances last season as the Imps won promotion to League Two.
"I enjoyed my time here last year. It was a great season and I believe the club is moving forward," Woodyard told the club website.