Sixty years ago thick smog descended on London, contributing to the deaths of an estimated 4,000 people.

The four-day "pea-souper", while worse than usual, was a familiar experience for Londoners.
Visibility was so poor buses and taxis ground to a halt, forcing commuters to hurry underground to use the Tube.
In the Isle of Dogs in east London, the fog was reported to be so thick people could not see their feet and animals dropped dead at the Smithfield Show.
According to the Met Office "the smoke-like pollution was so toxic it was even reported to have choked cows to death in the fields".
A Ministry of Health comparison between the excess of deaths registered in the weeks ending 13 and 20 December and those occurring in the preceding weeks produced estimates of the number of deaths caused by the smog ranging from 3,412 to 4,075.
By Peter CockroftMeteorologist, BBC London
Winter arrived early in 1952 and very cold snowy weather in November continued into December.
Londoners tried to keep warm by burning lots of coal on their home fires. This extra domestic smoke added to that belched out by power stations and factory chimneys.
As an area of high pressure arrived over the capital, the skies cleared and the wind fell light. On 5 December fog started to form.
In a "high" the air is pushing down - exerting a higher pressure. So, anything in the lowest part of the atmosphere becomes trapped; in this case the noxious combination of smoke and fog - smog.
Because the winds remained light there was nothing to blow it away.
Thousands of tonnes of soot and carbon dioxide were pumped into London's air, made worse by some of the fog droplets turning into harmful acids.
Little wonder then, at the time, Londoners described "gasping for air".
According to the General Register Office, respiratory diseases alone accounted for 59% of the increase in deaths registered in the week ending 13 December and 76% in the following week.
The main pollutant, sulphur dioxide, was linked to coal burning which was said to have reached exceptional levels.
The legacy of the Great Smog was the Clean Air Act of 1956 which introduced a number of measures to reduce air pollution.
Furnaces could no longer emit "dark smoke" and households were offered grants towards the cost of converting their coal-burning grates to smokeless fuel.
A broad consensus believed the legislation had a major impact on improving public health.
But new pollution threats are causing concern as air pollution mortality figures remain almost the same.
Lawyer Alan Andrews, of environmental organisation ClientEarth, said an estimated 4,300 Londoners now died each year as a result of air pollution (29,000 UK-wide, according to the Department for the Environment, Food and Rural Affairs).
This is no longer because of coal fires but is put down to nitrogen dioxide caused mainly by traffic fumes, he said.
"The UK is failing to meet European Union (EU) air quality standards.
"London is thought to have the highest levels of nitrogen dioxide of any capital city in the EU, with levels on some of London's busiest roads, such as Brixton Road and Putney High Street, currently more than triple legal limits," he said.
ClientEarth says the government's own plans show 16 regions and cities will not achieve legal limits for air quality until 2020, and London will have "illegal levels of air pollution until 2025".
Dr Frank Kelly, professor of environmental health at London's King's College, said legislation worked in the 1950s to deal with pollution but new laws were needed now.
"There's been a dramatic increase in car ownership and traffic, more taxis and buses,  so it's a new type of pollution. Legislation is once again required," he said.
He said the introduction of the Congestion Charge in 2003 and the Low Emission Zone (LEZ) in 2008 had only made a "tiny difference" to air quality in the capital.
Dr Kelly said air quality was known to be a key factor in the UK's biggest health problems - heart disease, strokes and diabetes.
"We've known this for the last decade but politicians are only just waking up to it. We need to clean the air up," he said.
Under EU air quality laws daily pollution levels must not be above the legal limit on more than 35 days in a calendar year.
But air pollution levels in London had already exceeded EU daily limits 36 times this year by April.
A Department for the Environment, Food and Rural Affairs (Defra) spokesperson said: "We want to keep improving air quality and reduce the impact it can have on human health and the environment.
"Our air quality has improved significantly in recent decades and is now generally very good, and almost all of the UK meets EU air quality limits for all pollutants.
"London, like many of our big cities, is one of the limited areas where air pollution remains an issue.
"However, air quality plans outline all the important work being done at national, regional and local level will ensure we meet EU limits as soon as possible."


Cardiff City manager Russell Slade says there is little significance to his side's rise to second in the table but insists promotion remains the aim.

The Bluebirds maintained their unbeaten start to the season with a 2-0 win against Huddersfield on Saturday.
But Slade says it is premature to place much importance on the Championship table after only six games.
"Our ambition is to be in the top six come May and that will never change," he said.
"I will look at it [the table] after 12 games because I think that's when things settle down a little bit.
"It's too early to start thinking who's going to be up there and who's going to be down there.
"Obviously three wins and three draws and being unbeaten is a sound start to the season."
Victory against Huddersfield was Cardiff's third in succession in the league, the first time they have done so since winning promotion to the Premier League under Malky Mackay during the 2012-13 season.
Slade has been in charge since October 2014 and oversaw a turbulent last campaign that saw Cardiff finish 11th in the Championship table.
Now in his first full term at the helm, the former Leyton Orient boss feels this is the time for his work to be judged fairly.
"I understand football managers are judged every day, every game," said Slade.
"When I came into the club there was a lot of work that needed to be done. One day I'll maybe tell you everything.
"A lot of things had to be addressed before you move forward and, if you don't get out of that and address it, then the spiral can continue downward.
"It was important to stop that spiral at source as quickly as possible. I think we've done that.
"I think I've given us stability now and I think everyone can look forward and look up."
Cardiff are four points behind Championship leaders Brighton and one ahead of Middlesbrough in third.
The Bluebirds host sixth-placed Hull on Tuesday in a match which pits them against a team relegated from the Premier League last season and have been tipped for an immediate return.
Slade, however, is not too concerned about the promotion race at this early stage of the season.
"I'm firmly concentrating on performance. I just want to see progression," he added.
"We've used the word transition, stability and towards the back end of last season we saw a bit of progress.
"We've seen a bit more progress now, which is what we all desire."


Wales women's footballer Jess Fishlock says more must be done to provide an environment in which gay players feel comfortable to come out.

Fishlock, 29, has previously spoken about the challenges she has faced as a high-profile gay athlete.
No current Premier League players are openly gay but a recent BBC survey found 82% of fans would have no issue with a gay player.
"The environment and the timing is so important," Fishlock said.
"That's what we have to get - the environment to say 'it's ok and it's not a problem'. That's what we're fighting for and what we've got to work on."
She told BBC Radio Wales Sport: "You don't want a footballer to come out for all the wrong reasons and then have a negative impact for that person.
"What you do want is for them to feel comfortable that they can come out, they can be themselves and they're happy with that."
Former England women's captain Casey Stoney publicly revealed her sexuality for the first time in February 2014 and became the most high-profile active gay footballer in England.
Stoney said homosexuality was more accepted in the women's game than the men's game.
Justin Fashanu was the first player in England to come out as gay in 1990, but took his own life aged 37 in 1998. No male professional player has come out while playing in England since.
The Seattle Reign player, currently on loan at Melbourne City, said she had received abuse during her career for being gay but was also proud she had inspired others come to terms with their own sexuality.
"I've had people write letters telling how me being so open and so happy and so comfortable with who I am at the highest level at a huge sport has actually made them realise it's ok and they don't have to commit suicide or they don't have these dark thoughts anymore," she added.
"When you hear that and when you get that I guess nothing else really matters because that is such a big thing to have."
Ex-Germany and Aston Villa player Thomas Hitzlsperger became the first player with Premier League experience to publicly reveal his homosexuality in January 2014 after he had finished playing in England.
Football Association chairman Greg Clarke told a Commons Select Committee in October that Premier League players would still suffer "significant abuse" if they chose to reveal they were gay.
This weekend, football and rugby union will support a campaign helping to raise awareness of issues faced by lesbian, gay, bisexual and transgender (LGBT) fans and players.
The Rainbow Laces campaign, launched by LGBT equality charity Stonewall in 2013, aims to tackle homophobic, biphobic and transphobic attitudes in sport.
Rainbow flags will feature at Premier League fixtures, while referees will wear rainbow-coloured laces and Fishlock says she supports the campaign's aims.


The number of single-use plastic bags handed out by UK supermarkets has increased for the fifth year, rising to 8.5 billion.

The Department for Environment, Food and Rural Affairs found the number was up by 200 million on 2013.
A reduction in the number of plastic bags handed out by retailers was found in Scotland and Northern Ireland, where levies have been introduced.
From October large shops in England will have to charge for plastic bags.
All retailers with 250 or more full-time equivalent employees will have to charge a minimum of 5p for the bags they provide for shopping in stores and for deliveries.
Resource Minister Rory Stewart said that countries with the charge had seen a "dramatic fall" in the number of plastic bags taken from supermarkets.
He said a "significant reduction" in the number of plastic bags used could be expected in England after the introduction of a charge.
In England, the number of single-use bags from supermarkets rose from 7.4 billion in 2013 to just over 7.6 billion, the statistics from waste reduction body Wrap revealed.
In Northern Ireland the number of bags handed out fell by 42.6% following a previous drop of 71%, after a carrier bag charge was introduced in April 2013.
There was a 5.2% increase in Wales last year, but the number of bags handed out has fallen by 78.2% since 2010. A charge was introduced in October 2011.
In Scotland, which brought in a levy last year, there was an 18.3% decrease in the number of plastic bags handed out by retailers.
"The more bags we take, the more plastic makes its way into our environment, blighting our high streets, spoiling our enjoyment of the countryside and damaging our wildlife and marine environments," Mr Stewart said.
"Simple changes to our shopping routines, such as taking our own bags with us or using more bags for life, can make a huge difference in reducing the amount of plastic in circulation, meaning we can all enjoy a cleaner, healthier country."
In Scotland, the number of "bags for life" handed out quadrupled last year but in England they accounted for just one in 20 taken from major retailers.


Manchester United left-back Luke Shaw will miss the remainder of the season with a foot injury.

Shaw, 21, is set to see a specialist to determine the extent of the injury after a scan on Monday revealed he has ligament damage.
The England defender left the field after only nine minutes of Sunday's 1-1 draw with Swansea at Old Trafford.
United boss Jose Mourinho confirmed Shaw will not play again this season at a news conference on Wednesday.
"Shaw has an important injury and we are waiting for one more opinion before the medical department decides what to do," said Mourinho.
"But he is out for the season."
The Red Devils face La Liga side Celta Vigo in the Europa League semi-final first leg on Thursday.
Paul Pogba is fit to face Celta, with Chris Smalling and Phil Jones also ready to return, as is fellow centre-back Eric Bailly, who was forced off injured against Swansea.
"[Eric has] this kind of personality that fights against every problem, unless it's impossible," said Mourinho.
Manchester United have a maximum of seven games remaining this season, should they reach the Europa League final.


Three police officers and two staff have "cases to answer" following the shooting of two women at a puppy farm in 2014, inquiries have concluded.

The police watchdog criticised the two Surrey Police staff over a decision to return shotguns to John Lowe, who later murdered Christine and Lucy Lee.
Three officers had cases to answer over the arrest of Ms Lee's daughter Stacy Banner after the deaths, said the IPCC.
Mrs Banner said without police failings her mother and sister would be alive.
Surrey Police has sacked a staff member and is considering the other findings.
The Independent Police Complaints Commission (IPCC) associate commissioner Tom Milsom said an investigation painted "a deeply concerning portrait" of Surrey's firearms licensing.
He said: "We found a unit which lacked the necessary training and processes to manage such a serious responsibility, staffed by individuals who were failing to undertake their duties with rigour and due consideration."
He said investigators found Stanton Royle, firearms licensing supervisor, and John Crabb, a firearms licensing inquiry officer, did not check police intelligence on Mr Lowe, highlight the risks he posed from a previous threat-to-kill investigation, look at whether he was a danger to the public, make sufficient inquiries into an ongoing investigation, or consider historical information on him.
After Surrey Police agreed with the findings, a gross misconduct case was proven against Mr Crabb, who was dismissed without notice. Mr Royle retired before a hearing took place, the IPCC said.
A separate investigation about complaints made by Mrs Banner looked at her contact with family liaison officers and her subsequent arrest after her mother and sister were shot at Lowe's Farnham home.
An IPCC investigator's opinion was that a detective constable and a detective sergeant had cases to answer for misconduct, and a detective inspector had a case to answer for gross misconduct, which related to authorisation of Mrs Banner's continued detention and her further arrest.
Surrey Police said a decision would be made on what action to follow in due course.
On the firearms licence, the IPCC said Surrey Police had accepted recommendations including the need to ensure structured training for licensing officers, liaison between the licensing team and officers and appropriate consideration of medical information.
Mrs Banner, who has criticised the force's decision to return the firearms, said she now planned to sue the force.
She said: "It is devastating to see your worst fears confirmed in black and white about how those entrusted with the public safety can abuse and neglect their powers.
"But for the police's failings, my mum and sister would be here today."
Her solicitor, Sarah Ricca, said: "The IPCC recommendations in this shocking case include that the licensing team should liaise with officers investigating allegations against firearms license holders.
"In other words, the IPCC is recommending that licensing team staff do their job."
Surrey Police said the force seized Lowe's licence and a number of shotguns in 2013.
Its decision to return the weapons was criticised in two independent reports by Hampshire Constabulary and North Yorkshire Police, which prompted the IPCC investigation and a comprehensive review of firearms licensing in Surrey.
The force said the Crown Prosecution Service decided not to bring criminal charges against the firearms licensing officers.
Assistant Chief Constable Helen Collins said: "The safety of the public has always been our primary concern and it was extremely important to us that in light of these events, changes were made quickly and efficiently to ensure we could be confident in our decision-making practices."
She said Surrey Police had apologised to the women's families.


More than 133,000 customer accounts were breached by fraudsters in an attempt to upgrade and steal phones to sell them on, Three has said.

The UK mobile phone network provider said no financial information such as bank account details were accessed.
However, contract and billing data as well as details like job and marital status may have been obtained.
Eight customers have been unlawfully upgraded to a new device and in total, 133,827 accounts were breached.
Dave Dyson, chief executive of Three, which has nine million customers, said: "We believe the primary purpose of this was not to steal customer information but was criminal activity to acquire new handsets fraudulently."
In a statement, Mr Dyson apologised and said that the company was contacting all customers concerned.
He said: "Once we became aware of the suspicious activity, we took immediate steps to block it and add additional layers of security to the system while we investigated the issue."
This week, the National Crime Agency confirmed that three people had been arrested in connection with the data breach, including two men from Manchester and one man from Kent. All three have been released on bail pending further enquiries.


Northampton secured back-to-back wins by beating Walsall at a rain-sodden Sixfields, extending their unbeaten league run to 31 games.

Both sides had early chances in a bright start to the game as Northampton's Kenji Gorre spooned over and Amadou Bakayoko forced home goalkeeper Adam Smith into a fine save.
The breakthrough arrived on 24 minutes when Harry Beautyman delivered a pinpoint cross which Matty Taylor expertly guided into the far corner.
Beautyman twice went close to adding an immediate second, sending a low effort whistling wide and then shooting straight at Saddlers goalkeeper Neil Etheridge.
For Walsall, Kieron Morris screwed a long-range attempt wide and Scott Laird spurned a glorious chance to level when side-footing wide.
Etheridge brilliantly denied Alex Revell on two occasions in the second-half.
But he could do nothing about Northampton's killer second goal which came on 78 minutes when Revell confidently rolled home a penalty after Jason McCarthy had handled inside the area.
Reports supplied by the Press Association.
Match ends, Northampton Town 2, Walsall 0.
Second Half ends, Northampton Town 2, Walsall 0.
Attempt saved. Joe Edwards (Walsall) right footed shot from outside the box is saved in the bottom left corner.
Foul by Brendon Moloney (Northampton Town).
Amadou Bakayoko (Walsall) wins a free kick on the left wing.
Brendon Moloney (Northampton Town) is shown the yellow card.
Amadou Bakayoko (Walsall) is shown the yellow card.
(Northampton Town) wins a free kick in the attacking half.
Foul by Amadou Bakayoko (Walsall).
Jak McCourt (Northampton Town) wins a free kick in the defensive half.
Foul by Franck Moussa (Walsall).
Attempt missed. Scott Laird (Walsall) left footed shot from outside the box is close, but misses to the left.
Substitution, Walsall. Andreas Makris replaces Kieron Morris.
Goal!  Northampton Town 2, Walsall 0. Alex Revell (Northampton Town) converts the penalty with a right footed shot to the bottom right corner.
Jason McCarthy (Walsall) is shown the yellow card for hand ball.
Penalty Northampton Town. Alex Revell draws a foul in the penalty area.
Penalty conceded by Jason McCarthy (Walsall) after a foul in the penalty area.
Corner,  Northampton Town. Conceded by Neil Etheridge.
Attempt saved. Alex Revell (Northampton Town) right footed shot from outside the box is saved in the top left corner.
Corner,  Northampton Town. Conceded by Kieron Morris.
Hand ball by Jak McCourt (Northampton Town).
Substitution, Northampton Town. John-Joe O'Toole replaces Harry Beautyman.
Alex Revell (Northampton Town) wins a free kick in the defensive half.
Foul by Jason McCarthy (Walsall).
Attempt missed. Matthew Taylor (Northampton Town) right footed shot from outside the box is close, but misses to the left.
Foul by Alfie Potter (Northampton Town).
Scott Laird (Walsall) wins a free kick in the attacking half.
Substitution, Walsall. Simeon Jackson replaces Liam Kinsella.
Attempt saved. Sam Hoskins (Northampton Town) right footed shot from a difficult angle and long range on the right is saved in the bottom left corner.
Foul by Harry Beautyman (Northampton Town).
Kieron Morris (Walsall) wins a free kick in the defensive half.
Brendon Moloney (Northampton Town) wins a free kick on the right wing.
Foul by Scott Laird (Walsall).
Substitution, Northampton Town. Sam Hoskins replaces Paul Anderson.
Corner,  Walsall. Conceded by Brendon Moloney.
Substitution, Northampton Town. Alfie Potter replaces Kenji Gorré.
Substitution, Walsall. Franck Moussa replaces Maz Kouhyar.
Corner,  Walsall. Conceded by Brendon Moloney.
Attempt saved. Scott Laird (Walsall) right footed shot from long range on the left is saved in the top left corner.
Foul by Matthew Taylor (Northampton Town).


Sales in the UK's superyacht industry have reached their highest level since the 2008 financial crisis.

A report from British Marine, which represents the leisure, superyacht and small commercial marine industry, said superyacht revenues for the year to April 2016 had reached £605m.
Revenues for the whole sector rose 1.6% to £3.01bn, the first time the £3bn mark has been breached since 2008-2009.
However, the report predicted growth would slow during 2017.
It said uncertainty over Brexit negotiations was likely to curb demand.
Total revenue fell in the wake of financial crisis, reaching its lowest point in the financial year 2011-2012 of £2,85bn and has been gradually picking up since then.
Increased revenue from engine and equipment manufacturing, as well as a jump in sales of hire and charter boats, are believed to have driven the sales increase.
Exports for the year were down 0.7% to £882m but British Marine said that in the last few months the industry had benefited from the fall in the pound against the dollar and the euro since the referendum, as it has boosted buying power from overseas customers.
However, marine businesses surveyed for the report expected that the support from the strong pound would be a short-term benefit.
Howard Pridding, chief executive of British Marine, said: "The industry remains robust - revenue is growing and we are taking on more employees.
"Despite the post-referendum volatility impacting on business and consumer confidence, the industry remains bullish."
The report said industry growth was expected to slow in 2017 "as economic volatility increases closer to and during negotiations over the UK's exit from the European Union."
Sunseeker and Princess are the UK's biggest superyacht companies. Globally, the industry is the fourth largest in terms of turnover.


An "absurdly ambitious plan" for a Grand Prix circuit on the streets of McLaren's hometown has been unveiled by the Formula 1 team.

Woking in Surrey would join the ranks of Monaco and Singapore as one of F1's "most glamorous and iconic race locations", McLaren said, with tongue firmly in cheek.
The Woking International Circuit would be one of the world's "fastest and most demanding" tracks, it claimed.
Woking council welcomed the news.
McLaren said it was "a bit scared" about the authority's reaction to its "absurdly ambitious plan" given there would need to be extensive and costly re-profiling of many roads and local landmarks.
But in a hard-to-believe official statement, Jonathan Neale, McLaren's chief operating officer, said: "Why not? Why not bring Formula 1 to the streets of Woking?
"Obviously, aside from the huge social and financial commitment needed to set up the infrastructure, re-profile roads, re-lay Tarmac, fit miles of Armco, build grandstands, pay for race-hosting fees and gain approval and sign-off from the FIA, we don't see any barriers to our vision."
The circuit would take "full advantage of the market town's winding streets and fast multi-carriageways", with the paddock on floatable pontoons anchored along the Woking-Basingstoke canal.
Silverstone has been the permanent home of the British Grand Prix since 1987 but its future is uncertain after its owner confirmed it had activated a break clause to cease hosting the race after 2019.
If a Grand Prix is held in Woking, it would not be the first time that it will have seen the world's fastest drivers on its streets.
In 1998, F1 world champion Mika Hakkinen drove his McLaren car on a lap of honour around the town after clinching the title in Japan.
Zak Brown, executive director, said that event "lit a spark that started a fire that turned into a dream that we converted into an idea: to host a round of the Formula 1 world championship on our doorstep, in Woking".
Ray Morgan, Woking Borough Council's chief executive, said: "We look forward to receiving McLaren's proposal which would reinforce Woking's position on the world stage."


The High Court in Dublin is to resume a case in which a privacy campaigner is trying to block Facebook from sending EU citizens' personal data to the US.

Max Schrems wants the court to order the Irish Data Protection Commissioner to audit Facebook to see what material it passes on to the US authorities.
The privacy watchdog had previously said the transfers were protected under the Safe Harbour trade agreement.
But a fortnight ago the European Court of Justice ruled the pact invalid.
The ECJ said that as a consequence the Irish regulator was indeed required to examine Mr Schrems' complaint with "all due diligence" and ultimately decide whether to suspend transfers if it believed the firm was not providing an "adequate level of protection" to protect people's privacy.
Following the ruling, the Irish data commissioner sought guidance from the High Court about how it should proceed, resulting in the latest proceedings.
Mr Schrems alleges that whistleblower Edward Snowden's leaks demonstrate that Facebook - as well as other technology companies - "aids US spy agencies for mass surveillance" in breach of the EU's Charter of Fundamental Rights.
Facebook strongly denies providing "backdoor" access to the US intelligence agencies and says its data-transfer processes were reviewed by the Irish watchdog as recently as 2012.
The social network, whose European headquarters is in Dublin, has requested permission to voice its case at the High Court, but has yet to find out whether it will be permitted to do so.
"We believe it is critical that we join the proceedings so that we can provide accurate information about our procedures and processes, as well as to correct inaccuracies that already exist," a Facebook spokeswoman told the BBC.
Mr Schrems has previously cast doubt on what information the California-based company might provide.
"Facebook is very likely bound by 'gag orders' and is not allowed to confirm such cooperation with US authorities," he wrote earlier this month.
"Facebook spokespersons [who comment on the matter] typically do not have the necessary security clearance to know about such programmes themselves."
The case could set a precedent that influences how other EU regulators handle complaints about data sent to US-based computer servers for processing and storage.
A spokeswoman for the Irish Data Protection Commissioner said it was not yet clear when the High Court would rule on how the dispute should proceed.


One of the largest chapels in England - the St Nicholas' Chapel in King's Lynn, Norfolk - is reopening after a £2.7m restoration project.

The late 14th/early 15th Century structure had suffered from rotting timbers and damage to the roof angels caused by death-watch beetles.
The year-long restoration, by the Churches Conservation Trust, was part-funded by the Heritage Lottery Fund.
The church is known for the "stunning angel roof", said the trust.
Crispin Truman, chief executive of the trust, said: "I couldn't be more proud of the partnership between the people of King's Lynn and The Churches Conservation Trust which has made the rescue of this internationally important building possible. The roof angels of St Nicholas' were in danger of being lost forever before the community mobilised to help us save the chapel.
"Thanks to funds raised locally and the support of the Heritage Lottery Fund, St Nicholas' is now once again open for all to see in its full glory.
"As well as re-roofing of the building to preserve the incredible carved angels beneath it, the restoration work has included the installation of solar panels on the roof, and a state-of-the-art kitchen and toilets, which will help to breathe new life into the chapel."
Founded in about 1140, the chapel was re-built in the 14th and early 15th centuries from new wealth which came to the town from the Baltic maritime trade.
King's Lynn was once one of the most important ports in England, trading with the Baltic, northern Europe and beyond.
Dendrochronological analysis shows oak used in some of the woodwork tracery at the chapel is from trees felled about 600 years ago in Eastern Europe and imported to King's Lynn for use in the chapel.
A Chapel of Ease is in the parish of another church and was built to meet an expansion of a town for the convenience of parishioners.


Ferrari ended pre-season testing with the fastest lap times but there is absolutely no doubt that once again Mercedes are in the best shape heading into the new Formula 1 season.

There are 21 grands prix this year - the longest season ever - so reliability will be paramount and the mileage the world champions achieved was nothing short of remarkable.
They basically did an entire grand prix season in eight days in Barcelona - the same mileage as they managed last winter in 12 days.
That was 31% more than main rivals Ferrari. Which means they have 31% more data to work from going into the championship.
Mercedes already had a fast car and they have refined it, rather than make any huge changes, while Ferrari have revised quite a lot of features of their car.
And the Mercedes clearly does not lack for pace - when Nico Rosberg did finally put a set of soft tyres on, he was within spitting distance of the best times set by the Ferrari drivers on even softer tyres.
The signs are that Ferrari are closer this year. Last year, they were a second off the pace at the first race of the season and they still won three races and got in amongst it, scoring more podiums than they did in 2013 and 2014 combined.
They are moving in the right direction and, this year, it already looks as if they have reduced Mercedes' advantage. But the key for Ferrari will be whether they can qualify well.
Their record on Saturdays has been pretty woeful in the last few years, with only five poles this decade, whether it was Sebastian Vettel or Fernando Alonso leading the team. Last season they were closer, but still on average over the season 0.689 seconds behind Mercedes.
Whenever Ferrari made it on to the front row last year, they had a chance. They put Mercedes under pressure, exposed some weaknesses and were able to get in the mix.
If, as it appears, they are that bit closer again this year, Vettel could well make things awkward for Mercedes.
A lot has been made of the way Rosberg ended last season on a high, winning three races in a row, taking six consecutive poles and Hamilton seemingly unable to beat him.
Many have wondered aloud whether he can continue that run and put Hamilton under some pressure.
That remains to be seen. But there is no mystery to why 2015 ended the way it did.
Hamilton became a back-to-back champion with three races still to go. He had put a lot of energy into achieving that and, when the title was in the bag, he lifted off the throttle a little.
People should not underestimate the emotional investment a driver puts into trying to win a world title. It takes an awful lot out of you, so it's no surprise Hamilton was not on top form once it was settled.
The question is, can he kick-start all that again and come out of the blocks as he did last year, or is he going to be a bit subdued?
Hamilton's testing did not seem to go that well - he was talking about struggling on the softer tyres and Rosberg set quicker times than he did.
Testing is one thing; racing quite another. Rosberg was pasted by Hamilton at the start of last year and I suspect that was partly down to the effects of the way he lost the title at the final race of 2014.
I've been through losing a world championship at the last race, and I can tell you it takes a long time to get over it and come back again. You saw that with Mark Webber at Red Bull in 2011, and I think the same thing happened to Rosberg last year.
This year is a bit different - yes, Rosberg got beaten again in 2015, but he ended the season on a high rather than a low.
Maybe that was down to him being freed up psychologically after the title was lost. It could have been to do with a change in the car's behaviour following the increase in minimum tyre pressures late in the season. Perhaps once his baby daughter was born and he became a father, that was one more pressure out of the system.
I've seen Nico around Monaco a couple of times this winter and he seems pretty calm. I think he is in a pretty good place right now.
The first qualifying session of the season will set the tone. If it's a clean session and Rosberg can beat Hamilton, things could get very interesting.
Ferrari would love Vettel's team-mate Kimi Raikkonen to join the German in taking the fight to the Mercedes.
It looks as if the car suits Raikkonen better again this year, just as it did last year compared to 2014. But Vettel had about 0.4secs on Raikkonen last year and it's hard to imagine that gap will close much.
One thing that could help Ferrari is the increased freedom on tyre choice this year, with three types of tyres rather than two available each weekend, and teams able within restrictions to choose how many of each they want.
In the past, Ferrari have tended to go better the softer the tyre, so this could potentially help them and enable them to look at doing something different strategically.
Ferrari have chosen for their drivers exactly the same mix of tyres as Rosberg for Australia - with Hamilton the one out on a limb in choosing only one set of mediums and an extra pair of softs.
This offers Ferrari, and Rosberg, a chance to do one fewer pit stop than Hamilton in Melbourne, which could spice things up a bit.
Williams look like they are best of the rest, closely followed by the two Red Bull teams and Force India. That four-way fight looks like being pretty intense.
Red Bull are still using a Renault engine this year - although it is badged as a Tag Heuer after a sponsor. That power-unit has improved significantly over the winter, but it is still down on performance compared to Mercedes and Ferrari, which will make life difficult for Red Bull, especially during races.
Force India are feeling quite good about the balance and consistency of their car. They are unlikely to have the consistency to challenge Red Bull and Williams all the time due to the pace of development through the season the bigger teams will be able to achieve, but they will have a good go at it on certain types of circuit.
The manufacturer with the most room for improvement was McLaren's partner Honda. It looks better for them - but not better enough.
The biggest weakness of that engine - hybrid energy deployment - has been vastly improved. But it remains a long way down on overall performance and McLaren are still in the region of two seconds off the pace and still have one of the slowest top speeds.
One thing did stand out in pre-season testing, though - McLaren were the team with the biggest disparity between actual lap time and theoretical best lap time (when you put together all the best sectors achieved by a driver on different laps).
That can only be down to two things - either they are disguising their true pace a little; or the car is inconsistent in its behaviour.
If it's the first, it's not going to make a huge difference, perhaps a couple of tenths of a second a lap. If it's the second, that's bad news for Jenson Button.
He held his own very well against Fernando Alonso last year but will undoubtedly struggle more if the car is difficult to predict in the way it drives.
We already saw this a couple of times in 2015 - when the car was wayward, such as in Spain and Singapore, Alonso was suddenly a long way ahead. There's no-one better in a tricky car than Alonso; and Button struggles in one more than some others.
Whatever, that team still has a long way to go before they are where they want to be and contending for race wins and championships.
There will be a new qualifying format introduced at the first race of the season after what can only be described as a bizarre backwards and forwards process in the last couple of weeks.
First it was going to be introduced, then it wasn't, then it was but with tweaks, and then finally the original plan was agreed after all - all in the space of seven days.
I found it particularly ironic to hear Bernie Ecclestone say his company could not make the necessary changes to the timing systems and television graphics in the timescale, when they were asking the teams to do exactly the same.
Anyway, the new knock-out system has been brought in, not because there was anything wrong with qualifying in the first place, but in the hope that it could mix up the grids a bit as a result of teams making mistakes.
That could indeed happen to a degree. But one corollary is that the teams that are more efficient in terms of their tyre usage, their hybrid energy and general ability to crunch numbers will benefit - and they are the teams who are already at the front.
In the past, we've seen top teams - particularly Ferrari - miscalculate the cut-off time and end up being knocked out early. But now teams are going to have to be out on track to ensure they can respond when necessary.
I suspect what will happen is that teams will set a lap and then cruise around keeping their hybrid systems charged and their tyres up to temperature so they are able to do another lap if they need to.
Where it might have a negative effect is in the final shoot-out for the top eight positions. It's going to end up with only two drivers left - and it's quite possible that we'll know after the first sector of the lap who's going to be on pole.
And that's not ideal - after all, some people pay to see Saturday's action. There's an appeal in seeing who is the absolute fastest over one lap.
Allan McNish was talking to BBC Sport's Andrew Benson


US consumer protection agency the Federal Trade Commission (FTC) has filed a four-count legal complaint against carmaker Volkswagen (VW).

The FTC claims the German firm falsely advertised that hundreds of thousands of diesel vehicles were environmentally friendly,  when this was not the case.
In court filings, the FTC says US customers suffered "billions of dollars in injury" as a result.
VW has admitted using hidden software to bypass pollution-limit test levels.
Around 11 million vehicles globally have been fitted with the so called "defeat devices"
A VW spokesman said the firm had received the FTC complaint and "continues to co-operate" with all regulators.
In January, the Justice Department sued VW for up to $46bn (Â£32bn) for violating environmental laws.
Meanwhile, the troubled carmaker faces more than 500 civil law suits relating to emission levels, as well as suits from some US states.
A federal court judge has given the firm a 21 April deadline to come up with a plan to fix 600,000 cars that emit illegal levels of pollution.


Inexperienced referees "have gone berserk" in imposing yellow cards after a new rule was introduced in 2017, says ex-Wales star Jonathan Davies.

Media playback is not supported on this device
The rule states that any contact with the head in "reckless tackles" will be penalised with at least a yellow card.
Pro12 players from Ulster, Scarlets and Ospreys were sin-binned this weekend.
Davies told Scrum V: "It's a brilliant directive but it's not being refereed properly. They've gone to the letter of the law, and it's gone crazy."
The former union and league player wants referees to adopt a common sense approach, adding: "You know a high shot, you know a cheap shot, you know a fair shot and referees have got to understand the difference as well."
In September 2015, World Rugby's chief medical officer Martin Raftery told the BBC that the game's rules may have to change to reduce concussions.
On Friday, Ulster's Sean Ready was sin-binned for a tackle on Scarlets scrum-half Aled Davies in their 16-13 defeat in Llanelli.
Media playback is not supported on this device
Italian referee Marius Mitrea then awarded a penalty try to Scarlets that proved the game's decisive score.
Davies and fellow Scrum V pundit Sean Holley said Ready should not even have been penalised.
They also believe Ulster captain and wing David Trimble's attempted tackle on Aled Davies in the same passage of play, which appeared to connect with his head, warranted a yellow card, but went unpunished.
Scarlets lock Jake Ball was also sin-binned in that game - another decision that drew the ire of Davies and Holley.
In Ospreys win over Connacht on Saturday, Wales fly-half Sam Davies was shown a yellow card by Scottish referee Neil Paterson.
Media playback is not supported on this device
Ospreys boss Steve Tandy said the new laws are making the game "unreffable".
"Sam Davies goes into the tackle, he goes low, the player's falling on him because he's being dragged down and he (Sam Davies) hits and it's a yellow card," Davies said.
"It will be interesting to see if something like that crops up in England v Wales (in the 2017 Six Nations).
"Say England score a try or Wales have a player sent off for 10 minutes and lose the game, there's going to be absolute ructions."
Davies also spoke of a cousin who he says has been in a coma and suffered brain as a result of a tackle in a match.
The former Neath, Llanelli and Wales union player, said: "He made a tackle, a legitimate tackle under the hip and he got injured.
"So now we're worried about the ball-carrier, not the tackler.
"So if you're going down and (the attacker is) leading with an elbow and the knee or the hip, then the tackler's in danger of getting damaged as well."
Former Ospreys head coach and Bristol assistant Holley fears some fans will lose interest in the game if the trend continues.
He disagreed with Saracens boss Mark McCall, who described Richard Barrington's sending-off in their Premiership draw with Exeter as neither reckless nor dangerous.
Holley said it was a "dangerous effort".
Referring to events in the Scarlets v Ulster game, Holley said: "What Sean Reidy's done there is try to prevent the score, which is ultimately his job and it's, in our view, a good tackle - it's not even a penalty let alone a yellow card.
"Trimble's is perhaps the more malicious, dangerous one.
"As for Jake Ball and Sam Davies, crikey, we're going to switch people off the game here if we are going to be stopping the game and sending people off for that."


US Secretary of State John Kerry has warned his Russian counterpart that Washington will end Syria talks unless Moscow stops the bombing of Aleppo.

In a phone call with Sergei Lavrov, Mr Kerry said the US held Russia responsible for the use of incendiary and bunker bombs against the city.
The US state department said it was making preparations to suspend talks.
Aleppo has come under heavy aerial bombardment since the end of a ceasefire a week ago.
In response to Mr Kerry's phone call, the Russian Deputy Ambassador to the UN, Evgeny Zagaynov, said the "trend" of Russia being blamed for the attacks in Syria must stop.
"It's become a sort of unfortunate tradition that the majority of strikes on civilian facilities in Syria, without checking it ... is blamed on Damascus or Russia,'' he said.
But Moscow said on Wednesday they would send diplomats to Geneva to talk to the US about normalising the situation in Aleppo.
"On orders of the Russian president, we are ready to continue joint work with our American partners on the Syrian issue," the defence ministry said in a statement.
Some 250,000 people are trapped in the rebel-held east of the city. They are under siege from Russian-backed Syrian government forces, which have launched a fierce campaign to recapture the area. The bombardment has been among the worst in the history of the five-year conflict.
The US has accused Russia of taking part in strikes on civilian targets and possibly committing war crimes.
The two nations have been locked in talks in an attempt to revive a fragile peace agreement, but the US said last week that Russia had openly lied to the UN about its intentions.
At least 96 children have been killed and 223 injured in eastern Aleppo since Friday, according to the UN children's agency Unicef.
"The children of Aleppo are trapped in a living nightmare," said Unicef deputy executive director Justin Forsyth on Wednesday. "There are no words left to describe the suffering they are experiencing."
More than 170 people have been killed in east Aleppo since the beginning of the recent offensive, according to the UK-based Syrian Observatory for Human Rights, a monitoring group.
Air strikes continued to hit Aleppo's besieged eastern neighbourhoods on Tuesday night. Local medical workers said that two major hospitals were put out of service by the bombardment.
International medical charity Medecins Sans Frontieres (MSF) tweeted to say that both hospitals were out of service. Adham Sahloul, a spokesman for the US-based Syrian American Medical Society, which supports the two hospitals, said the two attacks took place at the same time, suggesting they were deliberately targeted.
UN Secretary General Ban Ki-moon denounced the reported attacks on the two hospitals as "war crimes".
Addressing crowds in St Peter's Square in Rome on Wednesday, Pope Francis decried the bombing of Aleppo, saying those responsible for killing civilians would have to answer to God.
Aleppo, once Syria's largest city and its commercial and industrial hub, has been divided roughly in two since 2012, with President Bashar al-Assad's forces controlling the west and rebel factions the east.
In the past year, government troops have gradually broken the deadlock with the help of Iranian-backed militias and Russian air strikes. Earlier this month, they severed the rebels' last route into the east and placed its 250,000 residents under siege.
Children in Aleppo have made up a large proportion of casualties from air strikes, according to aid groups. At least 100,000 children remain trapped in the eastern part of the city.
In the government-held west, 49 children were killed by rebel shelling in July alone, the New York Times reports, citing the Syrian Observatory for Human Rights.
On Tuesday, the US pledged to provide an extra $364m (Â£276m) in humanitarian aid to people affected by the Syrian war.
The World Health Organization (WHO) meanwhile called for the "immediate establishment of humanitarian routes" into Aleppo, where hospitals are running out of supplies and rubble-strewn streets are preventing ambulances from getting through.


Defending champions Saracens have been drawn in the same European Champions Cup group as runners-up Clermont Auvergne for next season's competition.

The London club retained their title with a 28-17 win over the French side at Murrayfield last month.
Last year's finalists are joined in Pool 2 by Northampton Saints and Welsh outfit Ospreys.
The San Mames Stadium in Bilbao, Spain will host the final, the first time it has been held outside the Six Nations.
In the Challenge Cup draw, beaten finalists Gloucester will be in Pool 3 next season with Pau, Zebre and Agen.


Kyle Bartley's late header gave Championship play-off hopefuls Leeds a win against Brentford.

In a first half of few chances, Bees striker Scott Hogan rightly had a goal ruled out for offside.
Luke Ayling hammered an effort over the bar from a Stuart Dallas corner before Souleymane Doukara dragged a shot wide as Leeds took control after the break.
The game looked destined to end level before Bartley headed home from a Dallas corner to send the hosts fifth.
The win means Garry Monk's men have won four of their last five league games.
They dominated possession and chances in the second half but missed the presence and cutting edge of striker Chris Wood, who was ruled out with a hamstring injury.
However, with time running out, Bartley flicked a header beyond Daniel Bentley.
Brentford, who had won their last two games, remain in 14th place.
Leeds head coach Garry Monk:
"We've won seven of our last nine home games and that's great, but it was obvious we weren't at our best today. I thought we looked tired, especially in the first 60 minutes.
"The sense was that it was going to be one of those days, but it was a great header from Barts and I think the roof came off the place when that goal went in.
"It's great to see that mentality, fight and spirit from the players to keep going right to the end."
Brentford boss Dean Smith:
"I'm very disappointed; I don't think we deserved that. For an hour we were very good and made a good team look average.
"It was a typical Championship game - chances were at a premium - and that's why it was so cruel to lose it at the end.
"It (the disallowed goal) wasn't justified. I've seen the replays and he was marginally onside. Sometimes you get them and today we didn't."
Match ends, Leeds United 1, Brentford 0.
Second Half ends, Leeds United 1, Brentford 0.
John Egan (Brentford) hits the bar with a right footed shot from the centre of the box. Assisted by Harlee Dean with a headed pass.
Corner,  Brentford. Conceded by Gaetano Berardi.
Attempt blocked. Maxime Colin (Brentford) right footed shot from the right side of the box is blocked.
Pontus Jansson (Leeds United) wins a free kick in the defensive half.
Foul by Scott Hogan (Brentford).
Goal!  Leeds United 1, Brentford 0. Kyle Bartley (Leeds United) header from very close range to the top left corner. Assisted by Stuart Dallas with a cross following a corner.
Corner,  Leeds United. Conceded by Ryan Woods.
Offside, Brentford. Andreas Bjelland tries a through ball, but Scott Hogan is caught offside.
Foul by Stuart Dallas (Leeds United).
Ryan Woods (Brentford) wins a free kick in the defensive half.
Substitution, Brentford. Yoann Barbet replaces Tom Field.
Corner,  Brentford. Conceded by Pontus Jansson.
Corner,  Brentford. Conceded by Luke Ayling.
Foul by Ronaldo Vieira (Leeds United).
Sullay Kaikai (Brentford) wins a free kick in the attacking half.
Substitution, Brentford. Sullay Kaikai replaces Lasse Vibe.
Substitution, Leeds United. Marcus Antonsson replaces Souleymane Doukara.
Offside, Leeds United. Liam Bridcutt tries a through ball, but Hadi Sacko is caught offside.
John Egan (Brentford) is shown the yellow card for a bad foul.
Kemar Roofe (Leeds United) wins a free kick in the attacking half.
Foul by John Egan (Brentford).
Substitution, Leeds United. Liam Bridcutt replaces Kalvin Phillips.
Substitution, Brentford. Josh McEachran replaces Nico Yennaris.
Attempt missed. Luke Ayling (Leeds United) right footed shot from the right side of the box misses to the left.
Corner,  Leeds United. Conceded by Tom Field.
Attempt missed. Souleymane Doukara (Leeds United) right footed shot from the left side of the box is close, but misses to the right. Assisted by Stuart Dallas.
Offside, Leeds United. Pontus Jansson tries a through ball, but Souleymane Doukara is caught offside.
Attempt missed. Luke Ayling (Leeds United) right footed shot from the right side of the box is too high. Assisted by Stuart Dallas with a cross following a corner.
Corner,  Leeds United. Conceded by Harlee Dean.
Substitution, Leeds United. Gaetano Berardi replaces Charlie Taylor.
Offside, Leeds United. Luke Ayling tries a through ball, but Kemar Roofe is caught offside.
Attempt missed. John Egan (Brentford) header from the centre of the box misses to the right. Assisted by Harlee Dean with a cross following a set piece situation.
Foul by Ronaldo Vieira (Leeds United).
Lasse Vibe (Brentford) wins a free kick in the attacking half.
Offside, Leeds United. Luke Ayling tries a through ball, but Kemar Roofe is caught offside.
Attempt saved. Harlee Dean (Brentford) header from the centre of the box is saved in the centre of the goal. Assisted by Ryan Woods.
Kyle Bartley (Leeds United) is shown the yellow card for a bad foul.
Foul by Kyle Bartley (Leeds United).


England and Australia will meet in a day-night Test for the first time during the 2017-18 Ashes series.

The five-Test series will begin in Brisbane on 26 November, with the day-night match taking place in Adelaide from 2 December.
The third Test will be in Perth - either at the Waca or the new Perth Stadium.
Melbourne and Sydney will host the traditional Boxing Day and New Year Tests respectively.
A five-match one-day international series will follow, starting on 14 January 2018.
A Twenty20 tri-series featuring the two sides and New Zealand begins in February, with three matches in Australia and four in New Zealand, including the final.
"We know how much Adelaide fans love this style of Test cricket," Cricket Australia chief executive James Sutherland said of the day-night match.
"We're expecting a full house next year in what is sure to be a great contest."
A statement from Cricket Australia explained it is working with the Western Australian Cricket Association and the Western Australia Government "on the possibility of hosting matches at Perth Stadium in 2017-18".
The Perth Stadium is a new 60,000-seater venue which has been planned as a multi-sport arena, also hosting rugby union and league, football and Australian Rules football (AFL). Its official website states that it will be open "for the start of the 2018 AFL season", which is likely to be March 2018.
23-27 Nov 1st Test, Brisbane
2-6 Dec 2nd Test, Adelaide (d/n)
14-18 Dec 3rd Test, Perth (venue TBC)
26-30 Dec 4th Test, Melbourne
4-8 Jan 5th Test, Sydney


Golf has gained "six-appeal" and taken a significant step towards finding a marketable short form of the game.

The European Tour's Golf Sixes, staged at the Centurion Club near St Albans, proved popular with players and fans and established itself as the blueprint for the sport's version of cricket's Twenty20 format.
Introducing the use of a shot clock on one of the holes is an idea that could swiftly be incorporated in existing long-form tournaments.
But this inaugural event also proved meaningful golf matches can be played over as few as six holes. They can be done and dusted in little over an hour and a decent tournament can be completed in a weekend.
This is just what golf needs with the current perception that it is increasingly losing out because it takes too long to play and watch.
Traditional professional golf becomes genuinely absorbing "down the stretch." Golf Sixes catapults us straight to that point with no preamble.
Every shot counts, making the importance of a good start paramount, but there remains the opportunity for dramatic fight-backs. This is a formula that serves so well cricket's IPL and Big Bash matches.
For spectators, there was plenty to watch and hear. Some of the stuff pumped through the microphones and speakers missed the mark but an engaging atmosphere was generated.
To make it work better they should employ announcers who know their subject and are capable of identifying all of the players and match situations.
Further gimmicks are not required, nor do we need our intelligence insulted when mediocre putts are described as "great".
Likewise, the celebrity aspect of the television coverage grated somewhat and we did not need to be constantly told of the tournament's success in such sycophantic terms.
We could see for ourselves that it was worth watching.
It could have been bettered if the players wore microphones - listening to tactical discussions would have enhanced the coverage and the greensomes matchplay alternate shot format was a good choice.
But the most significant development was the shot clock used on the fourth hole. "I think it's a great idea," said England's Andy Sullivan.
During the first day of round-robin group matches, players were allowed 40 seconds to execute their strokes. That was reduced to 30 for the second day of knockout matches.
"What we found is when we're hitting, we had such a long time," Sullivan added.  "You've got ages, and it's embarrassing when you are playing on the Tour and it is taking that long.
"I think that's highlighted a lot of things, really, for the Tour."
Paul Peterson, of the United States, fell foul of the shot clock on the first day and it cost the Americans a quarter-final place. "He's probably humiliated," said Chris Wood, Sullivan's England team-mate.
"I think that's quite a lot to do with it, the naming and shaming. Sully is right, there's too much leniency I think.
"Players are to blame; hold your hands up there, but referees can be stronger on occasion."
European Tour chief executive Keith Pelley has identified slow play as golf's biggest enemy.  It would be a surprise if he is not considering proposing wider use of shot clocks.
He will also be wondering where next to take the Golf Sixes concept.
"I think it is definitely answering the cry from the global world of golf to be innovative and not be afraid of change," Pelley told BBC Sport.
"There needs to be another way to attract the younger generation. Is this the answer? Maybe, and we will take what is good out of this and build on it."
The Tour will examine player feedback - some felt the knockout matches should have lasted nine holes - and marketing data before deciding their next move.
"It will definitely be back next year," Pelley announced at the closing ceremony.
Certainly it feels as though his Tour has arrived on a concept that can complement the existing diet of predominantly 72 holes strokeplay.
It would work well under floodlights in big city venues where it is easier to attract big crowds. They are vital to generating an atmosphere commensurate with the excitement of the golf.
The inaugural tournament ended with Denmark winning the final against Australia on the closing green. Scotland came third, triumphing by inches in a nearest the pin shootout against England's quarter-final conquerors, Italy.
It was a fitting climax to a weekend that lays down a very encouraging and exciting marker for the future development of the game.


A Kenyan man accused of posing as a gynaecologist and allegedly raping women in his clinic after sedating them has appeared in court in Nairobi.

A national manhunt started after video footage broadcast on Kenyan TV appeared to show an unidentified man assaulting an unconscious woman on a clinic bed.
Mugo wa Wairimu has denied the allegations and said the report was an evil plot by his enemies.
Kenya's Medical Practitioners' Board says he is not a registered doctor.
The accused man was arrested on Thursday at a hotel outside Nairobi after members of the public called the police.
They accused him of operating a number of clinics in Nairobi without a valid licence.
He was taken to court to be charged but the prosecution said investigations were not complete.
Mr Wairimu will be detained for two weeks while police carry out further enquiries.
The BBC's Odhiambo Joseph in Nairobi says the court was told that releasing Mr Wairimu might endanger his life because of growing public outrage, something his lawyers did not oppose.
Mr Warimu was not asked to enter a plea.
Four women have lodged official complaints with the police so far over claims of sexual abuse.
Citizen TV said on their report, which was broadcast on Sunday, that they do not know the identity of the woman in the video, which was filmed by a suspicious staff member, or if she is aware of the alleged assault.


The Welsh, Scottish and Irish Rugby Unions insist their clubs will not participate in any European competition unless it has the "full approval" of the International Rugby Board (IRB).

English and French clubs will quit the Heineken Cup next year and have proposed the rival Rugby Champions Cup.
Scottish Rugby encourages all parties to fully engage in meaningful negotiations
But the IRB says all competitions must be run by unions and not clubs.
The Scottish Rugby Union (SRU) said it is "fully committed to the development of a pan European rugby competition".
The SRU, which stressed any competition must be supported by national governing bodies as well as the IRB, added: "We welcome the recent comments made by the IRB chairman, who confirmed that a pan European tournament remains the goal of the IRB - we are confident this can be achieved.
"Scottish Rugby remains committed to working with our colleagues across Europe and encourages all parties to fully engage in meaningful negotiations."
Statements issued by the Irish and Welsh Rugby Unions, whose sides play in the RaboDirect Pro12 league alongside the Scottish regions, were worded in a near-identical fashion, and their stance was backed by the Italian federation as well.
Bruce Craig, the deputy chairman of English clubs organisation Premiership Rugby, warned on Wednesday that Pro12 clubs face "financial oblivion" if administrators try to thwart proposals for the Rugby Champions Cup.
Craig has been central to the English and French clubs' plans to set up the new competition in place of the Heineken Cup, a tournament Craig says is "finished - it's over".
"If the competition [Rugby Champions Cup] is not approved then that would have absolutely catastrophic implications for Celtic rugby," Craig told BBC Sport.
"Celtic teams would be without significant revenues. The Rugby Champions Cup is a way to save European rugby."
All the Pro12 clubs - from Wales, Scotland, Ireland and Italy - currently participating in the Heineken Cup and Amlin Challenge Cup, which are run by the company European Rugby Cup (ERC), have received invitations to join the Anglo-French breakaway competition.
Craig, who is also owner of English Premiership side Bath, believes every Pro12 team is prepared to sign up to the new competition, but that they are being held back by their national governing bodies.
He has warned the national unions against interfering, and also indicated that they and the International Rugby Board (IRB) could face court action if they attempt to stop the Rugby Champions Cup.
English and French clubs gave notice 15 months ago of their intention to leave the Heineken Cup at the end of the 2013-14 season, citing preferential qualifying criteria for Celtic sides and uneven distribution of revenues as their main reasons for quitting.


An Arizona man has been convicted of providing support to so-called Islamic State for helping two men in an attempted attack in Texas in 2015.

Abdul Malik Abdul Kareem, an American-born Muslim convert, was sentenced to 30 years for what a judge called an "extraordinarily serious" crime.
His two friends were shot dead after opening fire at an event that featured cartoons of the Prophet Muhammad.
A security guard was wounded but no-one else was injured in the attack.
Kareem is the second person in the US to be convicted of charges supporting the so-called Islamic State (IS) group.
Gunmen killed at Prophet Muhammad cartoons event
IS claims US Prophet cartoon attack
Elton Simpson and Nadir Soofi were killed in a police shoot-out outside the conference in Garland, Texas, a suburb of Dallas, two years ago.
The event, organised by a group critical of Islam, included a contest for drawings of the Prophet Muhammad - such pictorial depictions are considered forbidden by many Muslims.
Prosecutors said Kareem had watched jihadist videos depicting violence with Simpson and Soofi, encouraged them to plot an attack to support the terrorist group and researched travel to the Middle East to join IS fighters.
Kareem told Judge Susan Bolton he "had nothing to do with this crime". He said he did not know his friends had been planning to attack the conference and only found out about the shooting after they were killed.
He also told jurors at his trial last year that he did not approve of Simpson using his laptop to watch al-Qaeda promotional videos.
But prosecutor Kristen Brook argued Kareem had played an active role in helping attempt mass murder.
"That just doesn't make him an outside participant or fringe guy," she said.
He was convicted of conspiring to support a foreign terrorist organisation and interstate transportation of firearms, among other charges.
Authorities also claim he inquired about explosives to blow up the Arizona stadium, which is where the Super Bowl was held that year, before deciding on the cartoon event.
Earlier this week, ex-convict Joseph Schreiber was sentenced to 30 years in prison for setting fire to a mosque that the Orlando nightclub shooter had occasionally attended.
Schreiber pleaded no contest and was also ordered to pay $10,000 (Â£7,986).  in compensation, despite damages to the mosque exceeding $100,000.


A woman was raped by a "controlling and verbally abusive" former speedway world champion, a court has heard.

Michael Lee, 55, of Worlington, Suffolk, denies raping and assaulting one woman and two sexual assaults against another between 2011 and 2012.
Mr Lee, a former co-promoter of the Mildenhall Fen Tigers speedway team, told police that the sex was consensual, Ipswich Crown Court heard.
The trial, adjourned until Tuesday, is expected to last about 10 days.
Opening the case, prosecutor Charlie Myatt told jurors Mr Lee was "controlling and verbally abusive" towards one of his alleged victims.
During his racing career, he was crowned speedway individual world champion in 1980 and rode for several teams including King's Lynn, Poole and Boston.
The prosecution claimed the woman said she was assaulted in a bathroom and injured her hand after being pushed over a toilet.
She also said the defendant threatened to put a plastic bag over her head.
Mr Lee told police the woman punched the wall herself and that he did not assault her nor put a bag over her.
The alleged sexual assaults are said to have taken place at a speedway party at a pub.
Mr Lee also told police they were "friendly squeezes on the bottom" and not sexual, the prosecution said.
The prosecution also told the jury about Mr Lee's convictions for possession, production and supply of cannabis in the 1990s.


Former CIA Director John Brennan has said an investigation into possible collusion between Trump campaign officials and the Kremlin is "well-founded".

He told the House Intelligence Committee he was aware of intelligence showing contact between Russian officials and "US persons involved in the Trump campaign".
Mr Brennan said the Russians "brazenly interfered" in last November's US elections and were "very aggressive".
But he said he did not know if the Trump campaign intrigued with Moscow.
Mr Brennan, who stepped down as CIA director in January, testified on Tuesday: "I encountered and am aware of information and intelligence that revealed contacts and interactions between Russian officials and US persons involved in the Trump campaign that I was concerned about because of known Russian efforts to suborn such individuals.
"It raised questions in my mind whether or not Russia was able to gain the co-operation of those individuals."
Trump-Russia scandal: How did we get here?
Trump trip memorable moments
His evidence undercuts President Donald Trump's claim that the investigation is a "taxpayer funded charade".
The White House said Mr Brennan's testimony "backs up what we've been saying all along".
"There is still no evidence of any Russia-Trump campaign collusion," the administration said in a statement.
The House inquiry is one of two congressional investigations into claims that Russian hackers tried to tip the presidential election in Mr Trump's favour last November, and whether members of his campaign aided the alleged Kremlin conspiracy.
The FBI also has its own investigation on the issue.
Mr Brennan added that he left office with many unanswered questions about Russia's influence over the election, but that the FBI's probe was "was certainly well-founded and needed to look into these issues".
Mr Brennan also told lawmakers that he had warned his Russian counterpart, FSB chief Alexander Bortnikov, during a phone call last August against meddling.
He told Mr Bortnikov any attempt to interfere would "destroy any near-term prospect" of repairing relations between Washington and Moscow.
Mr Bortnikov twice denied interfering and promised to bring up the matter with Russian President Vladimir Putin, according to Mr Brennan.
As CIA Director, Mr Brennan, along with the FBI and the Office of Director of National Intelligence, released an intelligence report in January concluding that Moscow attempted to influence the outcome of the election.
Days afterwards, Mr Trump strained relations with the intelligence community when he accused spy officials of leaking allegations that Russia had compromising information on him, likening it to "Nazi Germany".
At the time, Mr Brennan called Mr Trump's accusations "outrageous".
In a separate congressional hearing on Tuesday, Director of National Intelligence Dan Coats declined to comment on a report that Mr Trump asked him to publicly deny there was any evidence of collusion between his campaign and Moscow.
According to the Washington Post, Mr Coats and Admiral Mike Rogers, director of the National Security Agency, rejected Mr Trump's alleged request.
Meanwhile, the Senate Intelligence Committee announced plans to issue two new subpoenas - legal summons - to businesses owned by Michael Flynn, Mr Trump's fired national security adviser, who left after misleading the White House about his Russian contacts.
Mike Flynn 'lied' on security clearance
Also on Tuesday, Democrats on the House of Representatives Financial Services Committee wrote to the Treasury Secretary seeking "all pertinent financial records... that may shed light on President Trump's financial transactions with and business ties to Russia".
The letter, which was sent on committee letterhead, required approval from the panel's ranking Republicans in order to be sent.


The head of Indonesia's anti-drugs agency has proposed building a prison island guarded by crocodiles to house death-row drug convicts.

Budi Waseso said crocodiles often made better guards than humans - because they could not be bribed.
He said he would visit different parts of the Indonesian archipelago in order to find the fiercest reptiles.
Indonesia has some of the toughest drug laws in the world and ended a four-year moratorium on executions in 2013.
"We will place as many crocodiles as we can there," Mr Waseso was quoted as saying by local news website Tempo.
"You can't bribe crocodiles. You can't convince them to let inmates escape."
The plan is still in the early stages, and neither the location nor the potential opening date of the jail have been decided, the AFP news agency reports.


A man who became "well and truly stuck" after climbing a cliff to retrieve a frisbee had to be winched to safety in Gwynedd on Monday.

A coastguard rescue helicopter from Caernarfon was called to the scene at Porth Ceiriad, Abersoch at about 15:00 BST.
A Holyhead coastguard spokeswoman said the man had climbed up about 30ft (9m) to get the frisbee when he got stuck.
She said he was winched to the safety of the beach "a little embarrassed".
North Wales Police and the Abersoch rescue team also attended the rescue.


An eight-year-old boy died after a teenager fell on top of him during an indoor laser game, an inquest has heard.

Aryan Patel, from Leicester, died from internal injuries after the larger boy landed on him at Megazone Laser Tag.
The teenager told Leicester Coroner's Court he did not realise Aryan was there because of his slight build and the dark lighting in the room.
An inquest jury concluded Aryan's death in April was accidental.
The laser tag session included 33 other people who were above the age of six and taller than 3ft 7in (1.1m).
Aryan was carried into the arena's reception after the collision with the other player and was taken to Leicester Royal Infirmary.
He died nearly an hour after arriving at hospital from a liver injury and subsequent blood loss.
Leicester City Council told the court it will be taking no action against Megazone because it was satisfied with the company's health and safety procedures.
After the jury delivered its conclusion, coroner Lydia Brown praised the Patel family for their "quiet dignity" shown during the two-day hearing.
Ms Brown also offered her "sincere condolences" for what she described as an "unexpected and tragic outcome from a fun activity".
Speaking after the hearing, the Patel family said in a statement they hope Megazone will implement a number of changes to improve safety.
The BBC has contacted Megazone for a comment but the company is yet to reply.


Jo Cox's assistants, who were with the MP when she was murdered, have spoken about coping with the "surreal" loss of both a colleague and friend.

25 November 2016 Last updated at 18:30 GMT
Fazila Aswat and Sandra Major were leaving a car with Mrs Cox ahead of a surgery in Birstall, West Yorkshire, in June when the MP was shot and stabbed.


This afternoon Number 10 has bowed to the inevitable, and conceded that if (and it is still an if) the deal is done at the EU summit in Brussels this week David Cameron will hold a cabinet meeting as soon as he returns to London early on Friday evening.

A few weeks ago we reported very real concerns about the choreography in the aftermath of the summit from Eurosceptic cabinet ministers, worried that the PM would be setting the pace and terms of the debate in its vital early hours.
While they didn't commit officially to a position, the sense in Downing Street was that there was no need to shift cabinet from its usual Tuesday spot.
They hoped and expected that cabinet ministers who wanted to campaign for exit would keep their counsel until then, when the government had adopted its official position.
But in truth, at least one senior figure had already resolved to break their silence and reveal their plan to campaign for Out over the weekend, in defiance of Number 10.
With that knowledge, and several frank conversations with Eurosceptic ministers, David Cameron's team have decided to relent. This is not just a story for political process nerds (honest), but it illustrates how Eurosceptics, although in a clear minority in the cabinet, have been able to force Downing Street's hand.
This week's summit and now, the 24 hours that follow, are shaping up to be some of the most important in David Cameron's political career.


Northern Ireland runners Ciara Mageean, Kerry O'Flaherty, Paul Pollock and Kevin Seaward have been named on Ireland's Olympic athletics team.

The 17-strong team also includes North Belfast's Leitrim native Breege Connolly plus Donegal athletes Mark English and Brendan Boyce.
Mageean won a bronze medal at the European Championships on Sunday.
Pollock, 30, emphasised his readiness for Rio by finishing top Irishman in the half marathon in Amsterdam.
Holywood runner Pollock's weekend performance answered the criticism of his Olympic selection.
Pollock was preferred to Sergio Ciobanu for one of Ireland's marathon spots even though his qualifying time was 24 seconds slower than the Moldovan-born athlete.
Ciobanu appealed against his Rio omission in May but his plea was unsuccessful.
The Irish selectors were swayed by Pollock's impressive 14th place at the World Half Marathon in March and his previous good performances in major championships.
On Sunday, Pollock finished three minutes and 18 seconds ahead of Ciobana.
The Irish squad includes former world champion walker Robert Heffernan who looks set to be upgraded from fourth place to a bronze medal in the 50K at London 2012 following a drugs ban imposed on Russian winner Sergey Kirdyapkin.
Ireland's Olympic Athletics team
Ciara Mageean (1500m), Thomas Barr (400H), Kevin Seaward (marathon), Mick Clohisey (marathon), Paul Pollock (marathon), Kerry O'Flaherty (3000m steeplechase), Michelle Finn (3000m steeplechase), Sara Treacy (3000m steeplechase), Tori Pena (Pole Vault), Fionnuala McCormack (10,000m/marathon), Lizzie Lee (marathon), Breege Connolly (marathon), Mark English (800m), Alex Wright (20K/50K walk), Robert Heffernan (50K walk), Brendan Boyce (50K walk), Ciara Everard (800m)


A council is stepping up its efforts to ensure a major Viking treasure hoard is displayed in a new art gallery in southern Scotland.

The items were discovered in Galloway in 2014 by a metal detectorist.
Dumfries and Galloway Council wants to see them given a permanent home in Kirkcudbright.
It is in talks with National Museums Scotland (NMS) about a joint bid to secure the hoard and now plans to lobby MSPs to bring the treasure to the area.
Councillors were given an update on the situation at a meeting this week.
The local authority has already put Â£100,000 towards securing the hoard but it has been estimated total costs could be up to Â£1m.
The final decision on where the artefacts end up lies with the Treasure Trove Panel.
The council said there remained "ambiguity" about how a partnership agreement with NMS might work.
Talks are ongoing about how much of the hoard might appear in the new gallery being built in Kirkcudbright at any one time.
Responsibility for transporting the treasure between locations is also still under discussion.
Communities committee chairman Tom McAughtrie said the council would do everything it could to keep the treasure in the region.
"We've always maintained that the hoard was found in Galloway, so it should remain in Galloway," he said.
"A partnership agreement would allow this to happen, but we're still in negotiations with our colleagues from NMS to reach a deal that's of utmost benefit to our council, and to the people of Kirkcudbright.
"This hoard will bring in thousands of visitors each year to the region, so it is vital we do all we can to secure some sort of hold on the hoard."
He said they were now set to start a lobbying campaign to try to secure the hoard.
A further update on the position is expected before the council in March.


In an airy auditorium at Fung Kai Number One Secondary School in Hong Kong, about 900 students sat and listened as one of their teachers gave them a civics lesson.

The right to select their next leader is a key part of citizenship, they heard, as photos were shown of the three men running to become the city's next chief executive.
After the lecture, the students returned to their classrooms, where everyone took turns using computers to cast votes for the three candidates - Henry Tang, CY Leung or Albert Ho - as part of a city-wide mock election.
Hong Kong residents do not yet have the right to directly select their top official, but the desire for universal suffrage is strong, according to students and teachers at Fung Kai, one of the biggest schools in Hong Kong.
Eunice Leung, 16, is sharply critical of the current system, in which fewer than 1,200 electors largely loyal to Beijing will choose the Chinese city's top official on 25 March.
"They are given the right to choose the chief executive, but the decision they are going to make cannot represent all Hong Kong people. That's why it is a very unfair election," she said, after casting her vote.
Though it was meant to be a secret ballot, Ms Leung revealed she voted for Mr Ho, chairman of the Democratic Party, whose main platform is universal suffrage.
Because of his outspoken pro-democracy stance, Mr Ho is widely seen as being unacceptable to Beijing.
His two rivals are more familiar to the establishment.
Two systems
When Hong Kong rejoined China in 1997 after 150 years as a British colony, certain rights and freedoms not granted on the mainland were guaranteed here.
Among them was the right to elect the chief executive, a position roughly equivalent to mayor of Hong Kong, China's most international city and a global financial powerhouse.
But Beijing has dragged its heels on actually giving Hong Kong citizens that right.
Robert Chung, an influential pollster who organised the city-wide popular vote, said the desire for universal suffrage has been whipped up even more by a series of embarrassing scandals revealed during two months of campaigning.
"As it turns out, the election is getting more and more exciting. The candidates themselves are really trying to face the general public to gain support," he said.
Even though the candidates are not elected directly, they must win some level of popular support.
Otherwise, people may take to the streets to protest against a deeply disliked leader foisted on them, as they did in 2003, creating a crisis for Beijing.
While Hong Kong may lack some of the rights and institutions guaranteed in a democratic system, it does have a lively, free-wheeling press as competitive as any in the West.
In February, an enterprising Chinese-language newspaper published what it said were details of an enormous and illegal luxury basement belonging to the family of Henry Tang, one of the three contenders.
The news eventually set off a media frenzy, rare even for Hong Kong.
The candidate denied the accusations for days before finally confessing in an emotional press conference, where he blamed his wife.
"I apologise to the people of Hong Kong," the then-frontrunner said, adding he hoped the public would give him another chance.
Mr Tang, who had trailed the more populist Mr Leung in opinion polls, saw his public approval ratings sink further.
While "basement-gate" was probably the most memorable scandal uncovered by the media, Mr Leung has also been targeted.
Newspapers reported that some of his aides had attended a dinner in which a well-known gangster was present, leading to charges of triad involvement in politics.
Mr Leung has denied those charges.
What was meant to be a carefully choreographed leadership race has been upended by Hong Kong media.
The outcome of Sunday's election appears uncertain.
Some lawmakers have said that Beijing is now actively lobbying for the relatively more popular Mr Leung instead of Mr Tang, the previous favourite.
But election committee members have also been urged to cast blank votes to protest against the unprecedented mudslinging, amid concerns none of the three candidates are fit to run Hong Kong.
Several political parties and dozens of civic groups have vowed to take to the streets on Sunday to challenge what they call a "small circle election" decided by Beijing and the tycoons loyal to China.
Thousands of people are expected to take part.
The students at Fung Kai secondary school follow the news with interest. Ms Leung, the 16-year-old student, said she did not trust Mr Tang and Mr Leung because of the scandals that came to light.
"I think our future leader should have some important qualities. He should be honest. As you know, honesty is the best policy," she said.
Beijing has said it may allow Hong Kong citizens to choose their chief executive in 2017.
If that happens, then some of the students at Fung Kai will have the right to vote by the time they graduate.


The US Senate has passed a bill to approve the controversial Keystone XL pipeline, sending it to President Barack Obama's desk for a likely veto.

The 62-36 vote comes after weeks of debate and votes to amend the bill after the House approved it.
The 875-mile (1,400km) pipeline would carry tar sands oil from Alberta, Canada, to the US state of Nebraska where it joins pipes running to Texas.
The White House has previously said Mr Obama will veto the bill.
Spokesman Josh Earnest said the legislation would undermine a "well-established" review process.
Congress would need two-thirds of each chamber of Congress to overcome a presidential veto.
The project has pitted Republicans and other supporters, who say it will create much needed jobs, against many Democrats and environmentalists, who warn the pipeline will add to carbon emissions and contribute to global warming.
Senate Majority leader Mitch McConnell called the bill "an important accomplishment for the country".
"We are hoping the president upon reflection will agree to sign on to a bill that the State Department said could create up to 42,000 jobs and the State Department said creates little to no impact on the environment."
Democratic Senator Barbara Boxer called the bill "a disgrace".
"We tried on our side to make this a better bill and they turned us away."
Among the measures added the bill during the amendment process were energy efficiency measures, as well as on-the-record acknowledgement that climate change was not hoax.
The US president has been critical of the pipeline, saying at the end of last year it would primarily benefit Canadian oil firms and not contribute much to already dropping petrol prices.
A State Department report raised no major environmental objections in February, but the final recommendation was delayed amid a court battle over the project in Nebraska.
A final decision is expected in the upcoming weeks.
The state department is involved because the pipeline would cross an international border.
The Keystone XL pipeline aims to carry some 830,000 barrels of heavy crude a day from the fields in Alberta to Nebraska.
The oil would then be transported on existing pipes to refineries in Texas. The southern section of the project was finished last year.


A gang that targeted gold at the homes of wealthy Asian people across parts of north Wales, Shropshire, Merseyside and Cheshire has been jailed.

Nine members of the organised crime group were arrested following a joint investigation by North Wales and Cheshire Police.
Nearly 40 burglaries were carried out, with the stolen gold and goods worth over Â£100,000 taken.
The gold was the focus of thefts due to its high purity - and high value.
Mold Crown Court heard that police carried out surveillance before swooping on the gang in 2015.
The hearing was told the offenders would visit charity shops to buy clothes and trainers - and even Beatles-style wigs - before embarking on planned burglary expeditions.
"We began to develop a picture of the offending group we were dealing with and realised they were organised and sophisticated," said Det Insp Lee Boycott, who helped lead Operation Analogue.
"I believe the gang gathered information on the houses and the people they wish to target. They were not opportunist thieves, but planned meticulously what they did.
"It soon became apparent that overt and covert policing tactics would be required to catch them."
The operation even involved bugging one gang member's car, with one of the conspirators overheard bragging he had so much money he did not know what to do with it.
The thieves would use stolen or cheap cars to cover their tracks, while using bleach to wash down crime scenes to avoid detection.
"Their methods were carefully planned and sophisticated," prosecutor John Philpotts told the sentencing hearing.
Sentencing the nine men, Judge Niclas Parry said they had "caused great concern to the Asian community".
Dr Farookh Jishi, a retired surgeon and leading member of the Asian community in north east Wales, said the burglaries had left people scared in their own homes.
"It has caused a lot of fear and apprehension," he said.
"You know, just going out for a short time to pick children up from school and things, you don't know what to expect when you get back home.
"People have stopped keeping jewellery at home and hire safe deposit boxes.
"Day-to-day life has changed."
Speaking after the sentencing, Det Insp Giles Pierce from Cheshire Police added: "Burglary is a despicable crime as it targets people in the one place they should feel safest-in, their own home. We take any incidents of this nature extremely seriously and the sentences passed down today reflect that."


The chief executive of Arm Holdings, whose computer chip technology powers Apple and Samsung smartphones, is retiring after 12 years in the role.

Warren East, 51, is to step down on 1 July and will be replaced by Simon Segars, the current group president at the Cambridge-based company.
Mr East joined Arm in 1994 to establish its consulting business and became chief executive in 2001.
He said that now was the time for a change at the top.
"Arm is a great company with a strong market position and a unique culture," he said.
"We take a very long-term view about our business, and we believe that now is the right time to bring in new leadership, to execute on the next phase of growth and to plan even further into the future."
Under Mr East's tenure Arm has become the provider of processor technology for nearly all mobile phones and many other consumer and industrial electronic devices in use today.
The company develops designs that are licensed to customers and receives royalty payments every time devices with its chips are made by its clients.
In the last 12 years it has received royalties for over 40 billion Arm chips and the company's share price has risen threefold.
Arm chairman John Buchanan said: "Warren has transformed Arm during his time as chief executive."
At the news of Mr East's departure shares in the FTSE 100 Index company fell by 3% to just under 900p.


Seventy firefighters have been tackling a large fire at a former textile mill in Bradford.

At the height of the blaze, smoke could be seen from hills on the other side of the city.
West Yorkshire Fire Service was called to Ivy Mill on Mill Lane industrial estate in West Bowling close to the city centre, just before 08:00 BST.
There were still 60 firefighters at the site in the middle of the afternoon, the fire service said.
No one is believed to be trapped inside the building and there is no threat to residents, the fire service said.


An annual gay rally in Singapore has drawn thousands amid an unprecedented backlash from religious groups.

Pink Dot has been held every year since 2009. Attendees wear pink clothing and sit down for a mass picnic that ends with the forming of a pink dot.
But this year it falls on the eve of Ramadan, prompting an Islamic teacher to start a Wear White campaign against homosexuality, which has been supported by a Christian organisation.
Gay sex is illegal in Singapore.
Government leaders, as well as national organisations representing mosques and churches, have in recent weeks called on both religious and gay rights groups to act with restraint.
The Pink Dot rally proceeded peacefully on Saturday evening with no sign of anti-gay campaigners. Organisers said 26,000 people attended the event.
Wear White issued a statement saying it discouraged supporters from attending Pink Dot, as "it should be an event that no Muslim is associated with".
Some chose to go online instead to protest at the event.
About 4,000 people so far have taken part in a virtual rally called FamFestSG. Its Facebook page carries a quote from Prime Minister Lee Hsien Loong that defines the term family as "one man one woman marrying, having children".
The backlash has reignited the issue of gay rights in the largely conservative city-state.
In recent years, there have been two legal attempts to declare that the law banning gay sex is unconstitutional.
Singapore's government has said in the past that while it will retain the law to reflect mainstream society's stand on the issue, it will not be actively enforced.


Large parts of the world are still struggling with the burden dumped on their shoulders by the financial crisis - even now, eight years after its onset.

And there are dangers not far beneath the surface that could easily cause a new setback.
Even if those risks don't materialise, the outlook for this year, the IMF has said, is economic growth that is only "moderate with uneven prospects across the major countries and regions".
The recovery from the financial crisis and the Great Recession of 2008-09 continues and some areas do seem to be gaining some strength. The US is a notable example and there are signs that the eurozone may be putting the worst behind it.
But the global economy is still struggling to regain the momentum it had in the last decade, before the crisis. And then there are the risks.
The most topical case is the eurozone and the never-ending crisis in Greece. The latest developments suggest the eurozone will avoid, at least for now, the turbulence that a Greek abandonment of the currency might cause.
It is, however, a risk that remains lurking in the background. The mainstream view among eurozone governments and investors is that an exit would be very bad for the Greek economy and financial markets. But they think contagion to other parts of the eurozone, never mind beyond, would be containable.
Eurozone financial markets did wobble significantly at the start of the week, but then regained their composure. It's the bond market, where government debt is traded, which is where contagion to other countries' finances could take place.
There were moves in the direction you might expect if contagion were an issue - higher borrowing costs for Spain, Italy and Portugal and lower for Germany - but they were too small to be a problem. So far all countries bar Greece have borrowing costs in the bond market that are affordable.
That's not a universal view, however, and the US administration in particular has been wary about eurozone developments. The Treasury Secretary, Jack Lew, has repeatedly pressed European leaders to reach an agreement to keep Greece inside the eurozone.
Full coverage: Greek debt crisis
A bigger preoccupation for financial markets over the last year has been US interest rates. The Federal Reserve's main rate target is close to zero (actually a range of zero to 0.25%). It has been there since December 2008 in the depth of the recession.
The Fed will raise rates, probably later this year.  The economy is recovering and unemployment has fallen far from its peak.  Certainly, inflation is very low and the jobs market is not as healthy as the headline unemployment figure suggests.  But that just means the Fed will not raise rates very quickly once it has made a start.
The big concern about the rise when it comes is the potential impact on financial markets, especially in emerging economies. Higher interest rates in the US will encourage investors to move money back there, money that went overseas in the first place because rates were so low.
If that does happen it could force down the prices of the assets and the currencies that those investors sell.  When they sell bonds - which are a form of tradable debt - a fall in the price is in effect an increase in local financial market interest rates.
So the Fed move could lead to higher borrowing costs and a weaker currency, for many emerging economies, which in turn could mean higher inflation - because a declining currency makes imported goods more expensive.
We have already had one episode of this - it was known as the "taper tantrum"- when the then-Fed chairman Ben Bernanke signalled plans to cut back (taper) the quantitative easing programme of buying financial assets. It caused significant turbulence in a number of emerging economies, though they got through the episode without any major upset.
Would they survive unscathed again?  Perhaps, but there are risks and some economies are seen as a little vulnerable - South Africa, Turkey and Brazil, for example.
Economic growth in China has slowed, and that's generally reckoned to be a good thing. The 10% annual average over the last 30 years was widely thought to be unsustainable, too dependent on extremely high levels of investment.
The growth figure last year was 7.4% and the IMF forecast is for less than 7% this year.
There is a persistent concern that the slowdown might be bumpy - a hard landing as it's often called.
The property and stock markets are potential trouble spots. The IMF warned in April that "property price declines - especially in China - could spill over to emerging markets more broadly".
A more general deterioration in China's economic performance could affect suppliers of commodities - ranging from copper from Chile to iron ore from Australia and many more.
Why China's slowdown matters
Political events have the potential to disturb the global economy.  The current possible flashpoints are Ukraine and, as it so often is, the Middle East. So far neither has had a major impact on the global economy.
Indeed, one of the main economic dangers they pose, especially in the case of the Middle East would be a disruption of the crude oil market leading to a sharp rise in prices. But currently oil costs little more than half of what it did a year ago.
Full coverage: Ukraine crisis
Full coverage: Islamic State conflict
For the longer term, there's a question over whether the world will get back to pre-crisis growth rates.  Many rich and emerging countries have ageing populations. The effect may be partly offset by increased retirement ages, but it could still be a restraining factor for economic growth.
For the rich countries there is also a legacy of the financial crisis in the shape of lower levels of investment. Growth in emerging economies may be restrained as they approach what the IMF calls the "technological frontier".
They are getting closer to exhausting the relatively easy improvements in efficiency that can be achieved by adopting technology and business methods that are already established in more advanced economies.
There is a great deal of uncertainty with this longer term outlook, but there are reasons for suspecting that the world economy in the next few years will be a lot less exuberant than the period before the financial crisis.