Winston Reid scored a 94th-minute winner for West Ham at the London Stadium to condemn Sunderland to their worst start to a Premier League season.

The hosts may well have had a penalty when Reid was wrestled to the ground by Javier Manquillo early on.
Dimitri Payet then drew a smart save from Sunderland keeper Jordan Pickford before firing a low strike against the post after some clever footwork on the edge of the box.
Wahbi Khazri had the visitors' best chance after Steven Pienaar's deflected pass put him through on goal, but his tame shot was easily saved by Adrian.
Sunderland must have thought they had earned a point, but Reid turned smartly on the edge of the box from a West Ham corner to fire left-footed past Pickford.
It leaves David Moyes' side bottom of the Premier League with just two points from their first nine games this season.
West Ham's tricky start to life at the London Stadium has been well documented, with Slaven Bilic's side only picking up four points from four Premier League games at their new ground before Sunderland's visit.
Payet's wonder goal salvaged a point against Middlesbrough last time out in east London and eased some of the frustration the home fans have expressed since their move from the Boleyn Ground.
Those claret and blue-clad supporters were growing restless as the Hammers looked to have been held by the division's bottom side, despite dominating in the first half.
Moyes and Sunderland looked content to return home with a point as the former Everton and Manchester United boss threw on defensive reinforcements and watched his side drop deep into their own territory.
But it was a moment of hesitation deep into injury time that caught the visitors out, as a short corner from West Ham was worked to Reid and his effort snuck through a maul of bodies in the box.
Bilic opted to start with three central defenders as the Hammers recorded only their second win of the season at Crystal Palace last week, but the hosts were missing suspended left wing-back Aaron Cresswell, influential to that system, against Sunderland.
The Croat stuck with a back three in Cresswell's absence, handing Edimilson Fernandes a first Premier League start, and the 20-year-old Swiss looked an adept attacking threat, managing four shots on goal and making a key pass for the hosts.
On the other flank was Michail Antonio, the club's top scorer this season, and his pace and energy caused problems for the visitors with the England hopeful managing six crosses, as did his second-half replacement Sofiane Feghouli.
Despite the ammunition, summer singing Simone Zaza was unable to open his West Ham account, though the Italy forward did watch an acrobatic overhead kick drop narrowly wide of Pickford's far post before the break.
Sunderland have staged miraculous escape acts in recent seasons, but with just six goals and two points to show for his tenure so far, Moyes needs his side's fortunes to change quickly if they are to repeat that trick.
They are now only the second team in top-flight history to fail to win any of their opening nine league games in consecutive seasons, with Bury the other in 1905 and 1906.
Jermain Defoe's 15 goals played a big part in the Black Cats' successful survival bid last term, and the former England international has scored four of his side's six goals so far this season.
But the 34-year-old touched the ball just once inside the opposition box in the first half against his old side at the London Stadium and cut an isolated figure.
Moyes, who got the backing of Sunderland chief executive Martin Bain this week, sent his team out with more intent early in the second half with Khazri and Duncan Watmore posing more of a threat, though to no avail.
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Sunderland manager David Moyes: "It was offside. It should be given offside. The referee thinks it is onside.
"You can tell by the referee's movement to the linesman that he is not sure, they weren't sure but it was not a goal.
"I thought the players played well. Not in the opening 20 minutes, they bossed us but we got through it and had good chances. I am very pleased with the performance but not the result."
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West Ham manager Slaven Bilic speaking to BBC Sport: "It was a dramatic end. The first 25 minutes it was by far our best 25 minutes, including last season.
"We were good, sharp, created chances and we deserved to be two up. Then they came back. And in the second half they had great chances and were dangerous on the counter attack but in the last 15 minutes we pushed more and we were looking to score.
"I cannot say it was a goal from the training ground. You expect Winston Reid to score a header but it was a great decision to come in on the edge of the box."
Former England midfielder Danny Murphy:
"David Moyes thought the winner should have been ruled out for offside - and it was tight. But ultimately if you're conceding lots of goals late in games, you have got a problem.
"Players switched off and were not concentrating. As Winston Reid hits it, you can see Jonathan Calleri is in line with Jack Rodwell. It's an inch or two inches but it's not a bad decision. I think the assistant referee has done well."
West Ham are back at the London Stadium in EFL Cup action on Wednesday, when they host rivals Chelsea. Slaven Bilic's side then visit Everton in the Premier League for the 13:30 BST kick-off on Sunday.
Sunderland go to Southampton in the EFL Cup on Wednesday, before Arsenal visit the Stadium of Light in the Premier League's early kick-off on Saturday.
Match ends, West Ham United 1, Sunderland 0.
Second Half ends, West Ham United 1, Sunderland 0.
Goal!  West Ham United 1, Sunderland 0. Winston Reid (West Ham United) left footed shot from outside the box to the bottom right corner. Assisted by Dimitri Payet following a corner.
Corner,  West Ham United. Conceded by Lynden Gooch.
Attempt missed. Cheikhou Kouyaté (West Ham United) header from the centre of the box misses to the right. Assisted by Dimitri Payet with a cross following a set piece situation.
Billy Jones (Sunderland) is shown the yellow card.
Dimitri Payet (West Ham United) wins a free kick on the left wing.
Foul by Javier Manquillo (Sunderland).
Sofiane Feghouli (West Ham United) wins a free kick on the right wing.
Foul by Lynden Gooch (Sunderland).
Substitution, Sunderland. Billy Jones replaces Wahbi Khazri.
Substitution, West Ham United. Ashley Fletcher replaces Manuel Lanzini.
Wahbi Khazri (Sunderland) is shown the yellow card.
Substitution, Sunderland. Paddy McNair replaces Steven Pienaar.
Angelo Ogbonna (West Ham United) wins a free kick on the left wing.
Foul by Wahbi Khazri (Sunderland).
Mark Noble (West Ham United) wins a free kick on the right wing.
Foul by Lynden Gooch (Sunderland).
Substitution, Sunderland. Lynden Gooch replaces Duncan Watmore.
Attempt missed. Pedro Obiang (West Ham United) left footed shot from a difficult angle on the left is close, but misses to the left.
Dimitri Payet (West Ham United) wins a free kick in the attacking half.
Foul by Didier Ndong (Sunderland).
Foul by Jonathan Calleri (West Ham United).
Wahbi Khazri (Sunderland) wins a free kick in the defensive half.
Substitution, West Ham United. Jonathan Calleri replaces Simone Zaza.
Winston Reid (West Ham United) is shown the yellow card for a bad foul.
Hand ball by Jermain Defoe (Sunderland).
Corner,  West Ham United. Conceded by John O'Shea.
Attempt blocked. Simone Zaza (West Ham United) left footed shot from the right side of the box is blocked. Assisted by Dimitri Payet.
Mark Noble (West Ham United) wins a free kick in the defensive half.
Foul by Wahbi Khazri (Sunderland).
Foul by Pedro Obiang (West Ham United).
Wahbi Khazri (Sunderland) wins a free kick in the defensive half.
Attempt missed. Edimilson Fernandes (West Ham United) right footed shot from outside the box is too high. Assisted by Dimitri Payet.
Substitution, West Ham United. Sofiane Feghouli replaces Michail Antonio.
Offside, West Ham United. Dimitri Payet tries a through ball, but Simone Zaza is caught offside.
Offside, West Ham United. Adrián tries a through ball, but Simone Zaza is caught offside.
Attempt missed. Wahbi Khazri (Sunderland) right footed shot from more than 35 yards misses to the right. Assisted by Didier Ndong.
Corner,  Sunderland. Conceded by Michail Antonio.
Attempt blocked. Patrick van Aanholt (Sunderland) left footed shot from the left side of the box is blocked.


British cyclist Simon Yates has failed an in-competition drugs test - with his team blaming an "administrative error" over the use of an asthma inhaler.

Orica-GreenEdge said they took "full responsibility for the mistake" and there was "no wrongdoing" by Yates.
They added that he tested positive for the banned substance terbutaline and a team doctor failed to apply for a therapeutic use exemption (TUE).
They also said Yates will get their full support during the investigation.
"This is solely based on a human error that the doctor in question has taken full responsibility for," the Australian team added.
Yates, a former points race world champion, is regarded as one of Britain's brightest prospects on the road, along with his twin brother Adam. He is a strong contender to make the TeamGB road race team for the Rio 2016 Olympics this summer.
The sport's governing body, the UCI, notified British Cycling of a "potential anti-doping rule violation" at the Paris-Nice race in March.
Proceedings will be managed by the UCI independently, according to a spokesman for British Cycling.
"It would be inappropriate to comment further until the process has been completed," the spokesman added.
Yates, a climber with Orica, achieved a top-10 finish on the Mur de Huy stage of last year's Tour de France and was seventh in last month's Paris-Nice race.
The team are "concerned by the leak" of the failed test and are now submitting all evidence to the UCI.
News of the failed test is another blow in a bad week for British Cycling.
Technical director Shane Sutton resigned on Wednesday amid claims of sexism and discrimination. British Cycling is investigating claims the 58-year-old Australian used derogatory words to describe Para-cyclists, while an independent review will also look into rider Jess Varnish's accusations that Sutton made sexist comments and told her to "go and have a baby".
Sutton "rejects the specific claims" but said the allegations against him had "become a distraction" to British athletes before this summer's Rio Olympics.
A third inquiry was ordered on Thursday, with separate claims that official British Cycling kit was available to buy online. British Cycling denied any equipment provided by UK Sport had been given away or sold on for profit but said other unwanted kit from commercial partners is sold or given away.
Sutton was also asked to attend a meeting on Tuesday to discuss the kit allegations, revealed in the Daily Mail. UK Sport, which helps fund Britain's Olympians and Paralympians, ordered the investigation to "protect our investment in all sports on the world-class programme".
BBC sports editor Dan Roan
"This is now in danger of turning into the worst week in the history of British Cycling. Today sees the start of the sport's showpiece UK event - the Tour de Yorkshire -with more than a million people expected to watch the action. But it risks being overshadowed by a mounting crisis at the embattled national governing body.
"First came the damaging sexism and bullying allegations that cost head coach Shane Sutton his job. Then the revelation British Cycling was unaware Sutton was also being paid by Team Sky, followed by an investigation into whether team kit and bikes had been unofficially sold on.
"Now another grave blow, with rising star Simon Yates, expected to be part of TeamGB in Rio, failing a drugs test. All this just three months out from the Games. The timing could not be worse.
"For British Cycling, so often heralded in recent years for its record in both performance and participation, these are unusually dark days."


Russia is preparing wide-ranging economic sanctions against Turkey after Turkey downed one of its military jets on the border with Syria.

Prime Minister Dmitry Medvedev said the measures would be drafted within days, and could hit joint investment plans.
Also on Thursday, Russia's military suspended all communication channels with the Turkish military, including a "hot line" to help avoid air accidents.
Turkey says the plane violated its airspace - charges Russia denies.
Russia has sent troops and aircraft to Syria to back up the Syrian government of Bashar al-Assad in the civil war.
Turkey has been strongly critical of Mr Assad since the war began in 2011.
Tensions between Turkey and Russia have risen sharply. The US, the EU and the UN have appealed for calm.
Meanwhile, Russian President Vladimir Putin met his French counterpart Francois Hollande on Thursday and pledged Russia's support for a grand coalition in the fight against the so-called Islamic State (IS) militant group.
IS controls large swathes of Syria and Iraq and claimed the attacks in Paris earlier this month.
Where key countries stand on the Syrian conflict
Russia is tightening controls over food imports from Turkey, saying that 15% of the produce does not meet its standards. This is not the first time Russia has used food safety as a means of expressing its anger at a foreign state:
Russia mixes food and foreign policy
Turkey and Russia have important economic links. Russia is Turkey's second largest trading partner, while Turkey is the biggest foreign destination for Russian tourists.
Mr Medvedev said: "The government has been instructed to work out a system of economic and humanitarian measures in reaction to this act of aggression."
He said the focus would be on "the introduction of bans and restrictions with respect to the activities of Turkish economic structures on Russian territory" such as "shipments of goods including food" and "on works and services provided by Turkish companies".
"The same rules may apply to a whole range of investment projects," he also said. "Co-operation on them with Turkey was determined by a high level of trust with that country."
Russia has also advised its nationals against visiting Turkey, and urged those already there to return home "due to the terrorist threats that remain on Turkish territory".
The Russian SU-24 plane crashed into a mountainside on Syrian soil after being hit by a missile from a Turkish F-16 fighter jet.
One pilot was killed. The other one was rescued during a mission in which another Russian soldier was killed.
The Turkish military says the plane was warned 10 times over the space of five minutes to change direction before being shot at 17 seconds after it entered Turkish air space.
The surviving Russian pilot said Turkey had given no warning.
President Putin earlier complained that Russia had not received "a clear apology" from Turkish leaders, nor any offer of compensation or promise to "punish the criminals" over the downing of the jet.
"One gets the impression that the Turkish leadership is deliberately driving Russian-Turkish relations into a dead end," he said.
Turkey's President Recep Tayyip Erdogan has been defiant, saying his country does not need to apologise for violations of its airspace. However, he told France 24 television: "If we had known it was a Russian plane, maybe we would have warned it differently".
Turkey is a member of Nato. The alliance has backed Turkey's version of events, although it too is calling for "diplomacy and de-escalation" to resolve the situation.


Colombia has announced it is starting formal peace talks with the country's second largest rebel group, the National Liberation Army (ELN).

Government and ELN negotiators made the announcement in the Venezuelan capital, Caracas, where the two sides have been holding informal talks.
The two sides have been engaged in a five-decade-long conflict.
The announcement came as the government is nearing a final peace deal with Colombia's largest rebel group, Farc.
A joint statement was read by the former peace commissioner Frank Pearl and ELN rebel Antonio Garcia at the Venezuelan foreign ministry in Caracas.
The two sides said they had agreed on a six-point agenda for the formal peace talks which will start in the Ecuadorean capital, Quito.
However, the venue of the talks is likely to move to Brazil and Chile, among other places.
It was suggested that the negotiations between the government and the ELN stalled because the two sides could not agree on the place where the dialogue should take place.
Finally, they ended up with a complex agreement involving six countries.
That will certainly complicate the logistics of the negotiations and may end up causing delays.
But it seems that it was the only way of driving forward the peace process with the second largest guerrilla group in Colombia.
The issues to be discussed include how the rebels will lay down their arms and how they can take part in Colombian politics once a peace deal has been reached.
Colombian President Juan Manuel Santos welcomed the announcement, saying the ELN rebels "could and should play a part in the creation of peace" in Colombia.
"From the start of my time in office I have said that we have to put an end to this conflict, and if the ELN joins in with these efforts, then we'll have a more stable and lasting peace, which is what all Colombians want," he said in an address on national TV.
An estimated 220,000 people have died in Colombia in violence between the security forces, left-wing rebels and right-wing paramilitary groups since the conflict began in 1964.
Who are the ELN rebels?
The ELN and the government have been holding exploratory talks for more than two years in Ecuador, Brazil and Venezuela.
However, a number of ELN attacks and kidnappings have until now thwarted progress.
At the beginning of February, the head of the Colombian government delegation, Frank Pearl, warned the rebel group that "their time to reach a political solution to the armed conflict in Colombia is running out".
In the past weeks, the ELN released two of the hostages it was holding, paving the way for the announcement.
The ELN was founded in 1964 and inspired by the Cuban revolution of 1959.
One of its key figures was the priest Camilo Torres.
Since 1998, the ELN has been led by Nicolas Rodriguez Bautista, better known by his alias, Gabino.
Some of the most violent attacks by the ELN happened in the late 1990s.
In October 1998, 84 people were killed when the ELN blew up an oil pipeline in Antioquia province.
The group has also kidnapped and ambushed members of the security forces and local businessmen.
Last year, 11 soldiers and a policeman were killed in an ambush as they were transporting ballot boxes following local elections.


A 15-year-old girl has been airlifted to hospital after falling about 25ft down an embankment near Dunbar Castle in East Lothian.

Emergency service crews were alerted at about 14:50 and the teenager was said to be conscious when they arrived.
She was airlifted to Edinburgh Royal Infirmary by a helicopter from RAF Boulmer in Northumberland.
Two coastguard boats, paramedics and an air ambulance were also involved in the rescue.


The events which led to a child's death from an airgun shot in 1999 could happen again, a Welsh MP has warned.

Delyn Labour MP David Hanson told MPs that 13-year-old George Atkinson had died when a pellet hit his head after an airgun went off accidentally.
Mr Hanson said the law should require airguns to be stored in metal gun cabinets, with trigger locks for the weapons further improving safety.
Policing Minister Brandon Lewis said he would consider the suggestions.
The teenager, from Pontblyddyn in Wales, near Mold, was playing with another boy when an air gun accidentally went off.
Mr Hanson said that the pain of that loss remained strong for the family and they wanted further tragedies to be prevented.
He said that in the last 27 years, 17 children had died as a result of airguns.
"Sadly the circumstances of George's death could be repeated today unless further action is taken," Mr Hanson said.
The MP also said that the RSPCA had reported a 49% increase in airgun attacks on animals over two years, and the charity wanted the legal age for unsupervised use of airguns to be raised from 14 to 17.
Mr Hanson said that securely locking away airguns in a metal gun cabinet when not in use, as with other firearms, would be a "small but important change" which would deter young people.
Requiring trigger locks on the weapons would further improve safety, he added.
Responding for the UK Government, Mr Lewis said that public safety was the top of his agenda, but that it was important to strike the right balance.
He said everyone had to take responsibility to ensure that weapons are not handled unsupervised by those under the age of 18.
"What is reasonable can and will vary according to the circumstances," Mr Lewis said.
The minister said the UK government recognised that there were legitimate uses for air weapons, such as shooting sports, but confirmed he would look again at Mr Hanson's ideas.
In Scotland it will be a criminal offence to have an air weapon without a licence or permit from 31 December 2016.


Brighton striker Elvis Manu has joined top-tier Dutch side Go Ahead Eagles on loan until the end of the season.

The former Netherlands Under-21 international joined the Championship club from Feyenoord on a three-year contract in August 2015.
He has not started a league game for Brighton and spent two months of the 2015-16 season on loan at Huddersfield.
"The form of our other strikers has made it hard for Elvis to get game-time," said manager Chris Hughton.


Bees buzz between the blue and white painted hives.

There are light purple flowers growing in between the olive trees, rocks and brown grass. The sun burns.
"Don't go any nearer, otherwise you'll disturb the bees' movement, and they may sting you," beekeeper Khairi Kharroubi warns.
We are in the middle of the countryside in the Siliana province of Tunisia, a two-hour drive south west of capital Tunis.
Khairi, 24, and two other beekeepers are proudly showing some visitors their hives.
The three men are the first participants in a new social enterprise project called TuniBee, which is run by students at the Mediterranean School of Business (MSB) in Tunis.
Under the scheme, people with beekeeping experience are selected from deprived areas of the country.
Money from TuniBee's sponsors is then used to buy those taking part additional beehives. The beekeepers are also given training and guidance to produce better quality and larger amounts of honey.
Each hive costs 200 Tunisian dinars ($91; Â£69), and in return sponsors get 1.5kg of honey a year for a period of three years.
This is just over one-third of the current average annual production of a Tunisian hive, and 1.5kg of good quality Tunisian honey costs between 30 and 45 dinars.
The beekeepers get to keep the remainder of the honey during the three years, and after that period, the hive, and all its future honey production, is theirs to keep.
The idea for TuniBee came from Noomen Lahimer, professor of economics and entrepreneurship at the MSB, whose father keeps bees.
Prof Lahimer proposed it to his students, suggesting that they should set up and run the scheme as part of their studies.
"We immediately liked the idea," says MSB student Chaima Ben Romdhan, who is TuniBee's president.
"However, we didn't have any specialist expertise [of beekeeping]."
To bring in the required beekeeping knowledge, Prof Lahimer put his students in touch with a Tunisian entrepreneur called Khaled Bouchoucha.
Mr Bouchoucha, who had previously been mentored by Prof Lahimer in a competition for start-up companies in 2013, runs a business that specialises in helping beekeepers increase honey production.
His company, Iris Technology, has developed a beehive with a camera attached to monitor the movement of the bees. The hive is also fitted with a GPS tracker to try to deter theft - which is a growing problem in Tunisia.
In addition, the hives are fitted with a monitor that measures temperatures and humidity. If anything goes wrong, the beekeepers are sent a text message so that they can react as quickly as possible.
Mr Bouchoucha agreed to come on board and provide the beehives at cost price, and offer his company's technical support.
He has been joined by Hidhli Naoufel, a veterinarian who specialises in bees. Mr Naoufel has been training the participating beekeepers in best practice.
"Expertise is often lacking, and incorrect practices are adopted from generation to generation," says Mr Naoufel.
One example of bad practice Mr Naofel is preventing is bees being fed sugar. This increases a hive's production, but results in a bland honey lacking the flavours you get if the bees are required to harvest various nectars.
TuniBee currently has 24 sponsors, including parents and relatives of the students helping to run the scheme, and MSB staff.
Recently some of the sponsors joined the students on a coach trip from Tunis to the village of Kesra, in Siliana province, to meet the first three TuniBee participants and see their hives.
Mohamed Jouini, 32, says he was very pleased to have been chosen to take part.
An electrician, he says he needs to keep bees to make extra money: "The current economic situation in Tunisia makes it hard to survive with just one job."
Abdelfatteh Sayari, 38, has his TuniBee hives nearby. A mapmaker by trade, he started keeping bees as a hobby 10 years ago, keen to restart a family tradition.
He says: "My grandmother kept bees in the traditional way - in trees - but nobody took over from her when she passed away."
Fellow TuniBee participant Khairi Kharroubi has been helping his father look after bees since he was 12. He is currently doing a degree in business administration, so selling honey brings in vital money.
One of the sponsors who travelled to Kesra to see the bees is Salwa Battikh. A retired English teacher, the 50-year-old is the aunt of one of the students helping to run TuniBee.
She says: "I like the idea, it is something new and I hope it will succeed, because it is so hard to find good honey."
Like many Tunisians she usually buys her honey direct from beekeepers in the hope of getting better quality for a lower price than that available in supermarkets.
Ms Battikh adds that she hopes the scheme will encourage more people to go into beekeeping.
Another sponsor, the MSB's vice dean, Leila Triki, is hopeful that TuniBee can help alleviate poverty in the Tunisian countryside.
The intention is for the scheme to be expanded, including sponsoring a number of female beekeepers. TuniBee is also looking to bring on some corporate sponsors, with oil firms Total and Shell and computer giant Microsoft showing an interest.
Export sales are also being explored, with the students from TuniBee having already found one US company interested in importing Tunisian honey.
Currently Tunisia has 12,000 beekeepers who look after 256,000 hives, according to estimates by the Ministry of Agriculture. About 80% of those looking after bees do so to supplement their income from other work.
The hope is that the beekeeping skills the TuniBee programme teaches will enable beekeepers to increase production.
Presently the average amount of honey produced each year by a Tunisian hive is just 4kg, compared with 13.6kg in the UK and 34kg in Germany.
Economist Mehdi Ben Braham of the University of Carthage in Tunis says TuniBee is an "interesting project".
"This kind of project could have a significant socio-economic impact in deprived areas, by giving hope and creating sustainable jobs, and providing sufficient financial resources to reduce poverty."


MPs are preparing to vote on whether UK forces should bomb so-called Islamic State (IS) positions in Syria, but what is the legal basis for such an action?

The law does not require David Cameron to win a Commons vote before launching military action against Islamic State (IS) militants in Syria.
Politically, though, the prime minister cannot now proceed without a significant parliamentary majority.
In deploying its armed forces, the government acts under prerogative powers.
These are what remains of the powers that the sovereign enjoyed before the establishment of parliamentary government. They are now exercised by ministers on behalf of the Crown.
Because the UK's constitution is largely unwritten, nobody is quite sure how far the royal prerogative extends.
But everybody agrees that British service personnel operate under the command of the Queen and that the decision to go to war is one for the prime minister.
So there is no need for an act of parliament before troops are deployed.
In any case, legislation authorising each new military action would be impractical: there are occasions when troops need to be deployed at short notice or in conditions of secrecy.
And if a fresh act of parliament had been required for air strikes against IS in Syria, it would have needed approval from the Lords as well as the Commons.
In recent years, though, a convention has grown up around the use of military action.
That convention is still developing. It may even have changed this week.
A constitutional convention is a practice that is consistently followed by those affected by it - even though it is not legally binding.
It continues for as long as it proves useful but it can be ended at any time, merely by not following it.
And a convention of the constitution can be refined or modified when its suits ministers to do so.
For that reason, its scope and effect may be difficult to pin down.
The first time a government sought parliamentary approval for military action on a substantive motion was in 2003, when MPs approved operations in Iraq by 412 votes to 149.
The next was in 2011, when MPs approved military action in Libya - shortly after it had begun.
Then in August 2013, the Commons was recalled to vote on the principle of taking military action against the Assad regime in Syria, following its use of chemical weapons.
David Cameron was defeated by 285 votes to 272 and he respected the decision of the Commons.
From this point, it was possible to say that the UK's constitutional convention on the use of armed force required the prime minister to win a Commons vote on a substantive motion.
That view was buttressed in September 2014 by the Commons vote of 524 to 43 in favour of air strikes against IS in Iraq.
But it was still only a convention. It could be ignored by the prime minister if he thought he could win approval for military action from MPs and, ultimately, the electorate.
At the weekend, it was reported that David Cameron was seeking a majority of at least 30 in Wednesday's vote.
Although the prime minister did not commit himself to a figure, he delayed calling a vote until he could be sure of a substantial majority. So one can now argue that a very narrow vote in favour of military action would not satisfy the current convention.
Why has the prime minister painted himself into this constitutional corner? Why not use his powers regardless of parliament?
The answer may be both political and personal.
On a political level, he is less open to criticism if he can show that he has the support of most MPs. On a personal level, he can share responsibility for the inevitable casualties of war.
All this is entirely separate from the question of whether military action is lawful under international law.
The government says that its action amounts to self-defence, which is recognised by article 51 of the United Nations charter.
To be lawful, such force must be necessary and proportionate.
David Cameron told MPs last week that the IS campaign against the UK and its allies had reached the level of an armed attack, allowing force to be used "in self-defence to prevent further atrocities being committed".
Self-defence applies not only to defence of the UK but also to defence of its allies.
So the global coalition is acting in the collective self-defence of Iraq against attacks from IS in Syria.
This, said the prime minister, was "further underscored by the unanimous adoption of UN Security Council resolution 2249" which calls on member states to take "all necessary measuresâ€¦ to prevent and suppress terrorist acts" by IS.
But the resolution goes on to say that states must act "in compliance with international law".
That is why it was necessary to justify military action as collective self-defence.
The alternative would have been a resolution passed under chapter VII of the UN charter, under which the Security Council may authorise military operations by member states.
But that was clearly a step too far.
Instead, we have a resolution that provides political cover without additional legal authorisation.
As the Attorney General Jeremy Wright told MPs last Thursday, it was "extremely useful" but "not necessary", given the right to act in self-defence.


The backers of a museum honouring one of Scotland's greatest motor sport heroes have said they need another £300,000 by 21 April.

The Jim Clark Museum already has planning permission for the site in Duns in the Scottish Borders.
It has £1.3m pledged towards the £1.6m required to secure the project.
The latest backer of its crowdfunding appeal is former World Rally champion Louise Aitken-Walker, who lives in Duns.
Scottish Borders Council has pledged £620,000 towards the museum celebrating the achievements of two-time Formula One world champion Jim Clark, with a similar sum coming from the Heritage Lottery Fund.
Planning permission has been given, subject to the work starting in the next three years.
It is hoped the development could be completed by 2018 - the 50th anniversary of Clark's death at Hockenheim in Germany, aged just 32.
The driver was born in Kilmany in Fife, but raised in the Borders, and was crowned Formula One world champion in 1963 and 1965. He won a total of 25 grand prix races.


Acting Labour leader Harriet Harman is facing a revolt after ordering the party's MPs not to vote against the government's welfare bill.

Scores of Labour MPs are expected to defy an instruction to abstain on the bill, which includes plans to limit child tax credit to two children.
One MP, John McDonnell, said he would "swim through vomit" to oppose it.
Work Secretary Iain Duncan Smith said Labour was beset by "private arguments and internal fear and loathing".
A series of votes on the Welfare Reform and Work Bill in the next half hour is expected to expose Labour divisions over how to respond to benefit changes announced by the government in the Budget.
The Labour leadership originally said it would not oppose restrictions to in-work benefits, including curbs on child and working tax credits, part of £12bn worth of cuts sought by ministers by 2020.
But many in the Labour Party objected, with leadership candidates Andy Burnham, Yvette Cooper and Jeremy Corbyn among those to criticise the plan. Only the fourth candidate, Liz Kendall, supported the move.
Ms Harman tried to quell the revolt by tabling an amendment to the Welfare Reform and Work Bill setting out measures Labour backs and those it would change.
It offers support for the cutting household welfare cap to £20,000 a year (£23,000 in London), and moving mortgage support from grants to loans.
But it opposes the abolition of child poverty targets and changes to Employment and Support Allowance, paid to people who cannot work because of illness or disability. It makes no mention of the child tax credit change.
Ms Harman said if the amendment was rejected, Labour MPs would be expected to abstain in a subsequent vote on the general principles of the bill, leaving the way clear for it to be passed at Second Reading.
Leadership contenders Andy Burnham and Liz Kendall are expected to follow Ms Harman's lead but her approach has infuriated a large number of Labour MPs.
More than 60 signed a rival amendment tabled by MP Helen Goodman opposing all the changes but that amendment was not called for a vote by Commons Speaker John Bercow.
Shadow employment minister Stephen Timms said the party would fight "tooth and nail" to oppose those parts of the bill it disagreed with but added that there were things it could support and urged colleagues to remain "united" in Monday's votes.
Speaking as Monday's debate got under way, Mr Duncan Smith said Labour were on the wrong side of public opinion on the issue.
"The bill will ensure the right support and incentives are in place so people are always better off in work rather than trapped on welfare," he said.
"Yes, there are difficult decisions here, but what would be wrong would be to turn a blind eye, as the opposition did for so many years, and not face up to these difficulties.
"The bill puts work first and puts welfare spending on a more sustainable footing for the future while, at the same time, protecting the vulnerable and those most in need."
Writing in the Guardian earlier, Chancellor George Osborne said the benefit changes were in line with the views of most Labour voters and were a continuation of policies pursued by former Labour ministers.
The SNP, the Liberal Democrats and the Green Party have all said they will oppose the bill.
In his first Commons speech since becoming Lib Dem leader, Tim Farron said 500,000 people would see their Employment and Support Allowance cut by a third, a move which he said "demonised people with disabilities and mental health conditions".
"It will trap people on welfare, it will not liberate them," he said. "Labelling this bill progressive does not make it progressive".
SNP spokeswoman Hannah Bardell said the party had a mandate from the Scottish people to oppose "cruel" austerity measures.
"SNP MPs wish to work with a progressive alliance across the UK against the Tories' plans to make millions of families poorer," she said.  "It is not enough for Labour simply to abstain on the welfare reform bill - they must join us in voting against it."
However, with the government having a majority of 12 in the Commons, the bill is still expected to pass its first parliamentary hurdle.


Police are investigating the death of a German sailor whose body was found slumped in a yacht drifting off the southern Philippines.

Fishermen found the decomposing body inside the radio room of the yacht, which was floating 62 miles (100 km) off the coast near Barabo town in Surigeo del Sur province, police said.
Documents in the vessel indentified the man as Manfred Fritz Bajorat.
It is unclear what killed him or how long he has been dead.
Investigators found no obvious signs of violence. They are trying to retrace the man's final journeys and speak to the last people to have had contact with him.
Graphic photographs posted on Facebook  by local authorities appeared to show the body preserved in the radio room by hot, salty ocean conditions.
The man was found slumped over his right arm on a desk, with one hand near a telephone. Personal possessions were found scattered elsewhere in the yacht, according to reports.
The grim discovery was made on Thursday by local fishermen, led by 23-year-old Christopher Rivas, who reported it to police.
Forensic examiners believe the man died more than four days before the yacht, marked "Sajo", was found, Inspector Mark Navales, deputy police chief of Barabo town, told AFP.
"It is still a mystery to us," he said.
The yacht was later towed to Barabo on Mindanao island.
The German embassy in Manila has not commented on the reports.


The former best friend of a man found bludgeoned to death in one of the most exclusive streets in Edinburgh has been found guilty of the murder.

Kieran Davies, 28, had denied murdering Ashley Hawkins, 32, from Barry in Vale of Glamorgan, Wales, who was found dead in a flat in Scotland Street on 2 December 2016 at 05:30.
Sentencing was deferred for background reports at the High Court in Edinburgh.
Lord Boyd told jurors: "Murder cases are always difficult."
He added: "They are emotionally draining for everybody involved in it."
Police who were called to the second floor flat at 7 Scotland Street and forced entry found Mr Hawkins dead with catastrophic head injuries.
Unemployed Davies was the only other occupant of the locked property and was found topless, wearing jogging bottoms and trainers extensively stained with the dead man's blood.
A Reebok top, which Davies had earlier been seen wearing, was found in a washing machine, saturated with the victim's blood, along with brain tissue.
The court heard Mr Hawkins had suffered at least 24 blows to the head and a metal pole and broken hammer recovered from the flat could have been used as weapons in the fatal attack.
Davies, a prisoner in Edinburgh, was found guilty of murdering Mr Hawkins by repeatedly striking him on the head with weapons and repeatedly stamping and kicking him on the head and body.
Police were alerted to the incident in the early hours of the morning after neighbours heard banging and shouting coming from the flat.
One teenager was aware of 15 to 20 bangs and screaming which had stopped by the end of the disturbance.
The witness was confident that no one left the premises from the end of the banging until the arrival of officers.
Police found the front door of the flat was locked and entry was forced and an attempt was made to resuscitate the victim who was lying face down covered with a blanket and surrounded by a pool of blood.
Prosecutor David Taylor told jurors: "When police came into that locked flat there were two people there - one alive, covered in blood and one dead, violently murdered. There is no mystery in this case."
He said Davies and Mr Hawkins had come to Edinburgh from Wales "as best of friends" but added there was evidence that changed and there was friction between them.
Davies told police that he had taken Valium and claimed that he also had a needle of heroin and ecstasy.
A blood test later proved negative for ecstasy and opiate drugs but gave an indication that he had taken diazepam and cannabis.
Mr Stewart told the court that previously consideration had been given to Davies' fitness to stand trial and a psychiatrist who had seen him reported that he suffered from a delusional disorder.
Det Insp Stuart Alexander, of Police Scotland's major investigation team, said: "Davies continued to maintain his innocence throughout the investigation and trial, despite significant evidence of his guilt.
"When officers found him in the flat, he claimed to have no recollection of Ashley's death and has given no explanation for why he took the life of a friend.
"Davies subjected Ashley to a brutal and sustained attack and we welcome this conviction. I hope this helps Ashley's loved ones as they continue to come to terms with their loss."
Det Insp Stuart Alexander, of Police Scotland, said: "Davies continued to maintain his innocence throughout the investigation and trial, despite significant evidence of his guilt.
"When officers found him in the flat, he claimed to have no recollection of Ashley's death and has given no explanation for why he took the life of a friend.
"Davies subjected Ashley to a brutal and sustained attack and we welcome this conviction. I hope this helps Ashley's loved ones as they continue to come to terms with their loss."
Davies is due to be sentenced at Edinburgh High Court on 24 August.


The Belfast Giants-Edinburgh Capitals game will be finished on Saturday night after match officials wrongly called the match over after a 3-3 draw.

The Challenge Cup match in Belfast should have gone into sudden death overtime, and penalties if necessary, to determine the winning team.
Overtime will now be played ahead of the league game between the sides.
The Elite League apologised for "an on-ice error and  any inconvenience caused to supporters".
Craig Peacock, Mitch Ganzak on the powerplay and Colin Shields were the scorers for the Giants in Friday night's encounter.
Craig McCallum, Ryan Hayes and David Rutherford were on target for Capitals.


The dog that killed the eight-year-old son of Gambian President Adama Barrow has been put down, a government official has confirmed.

Habibu Barrow died in hospital after being bitten by the dog last month at his aunt's house in a coastal resort near Banjul.
The attack happened before Mr Barrow was inaugurated and while he was still in Senegal for his safety.
The president, who recently returned to the Gambia, missed his son's funeral.
Reports say that Habibu - one of the president's five children - was mauled by the dog and sustained a head injury.
It is unclear why the dog attacked the young boy.
The animal, which had been certified rabies free, was put down on Tuesday, with a quick procedure.
The government official said the dog belonged to the aunt and had not attacked anyone before.
He said the attack had worried the family and they were comfortable with the action taken.
"We thought it's not safe for the community if the dog was on the streets," the official said.
Many homes in the upmarket area of Fajara, where Habibu was staying along with his mother and other siblings, have security dogs to ward off intruders.
Mr Barrow, who won elections in December, was living in neighbouring Senegal at the time after the previous Gambian president, Yahya Jammeh, refused to step down.
He returned to the Gambia last week after Mr Jammeh agreed to leave the country.
Adama Barrow: From estate agent to president


Cardiff has an ongoing problem with the radicalisation of young Muslims, said an academic who has studied the issue.

Two men from the city have been identified taking part in what appears to be a Jihadist recruiting video, which was posted online last week.
It is thought Reyaad Khan travelled to Syria with friend Nasser Muthana who also appears in the footage.
Khan lived close to the Cardiff men jailed over the London Stock Exchange bombing plot in 2012.
It is believed the two men, both 20, travelled to Syria in November, while Nasser Muthana's younger brother Aseel, 17, travelled to the country in February.
The men are believed to be among 500 Britons fighting in the conflict in Syria.
Reyaad Khan's family is said to be frustrated that more could not be done by the authorities in the UK to bring him home and were concerned he would be radicalised after he went missing.
Dr Suraj Lakhani, of Cardiff University, who recently completed his doctorate - A Social Analysis of Radicalisation in the UK, told BBC Radio Wales: "As far as I'm aware, there has been an issue in Cardiff for a while now.
"This is a concern that has been raised not only by the intelligence services and the Welsh government, but also South Wales Police and local Muslim communities.
"People have been saying that something needs to be done in Cardiff, they need support.
"There has been a threat for a while as there has been in other parts of the country as well. Yes, there has been a threat and it's still ongoing."
He said he believed the internet played a "big role" in radicalisation but there was also "face to face interaction", although not from the mosques.
That was echoed by Saleem Kidwai, secretary general of the Muslim Council of Wales, who insisted there was no problem in south Wales mosques.
He believes the men may have travelled to Syria for humanitarian reasons and were radicalised there.
He said Islamic leaders and scholars could provide an important role in the fight against radicalisation.
"People who are radicalising these youngsters probably are misquoting the verses from the Koran and the hadiths of the prophet for their own political ends, rather than what the true picture is," he said.
"It is only the scholars of Islam - they can give the true interpretation of it, which I know is very different than what the extremist ideologists are portraying."
BBC Wales reporter Jordan Davies
I am at the South Wales Islamic Centre in Cardiff where Nasser and Aseel Muthana prayed some time ago now before moving on to other mosques in the city.
I think it is fair to say there has been widespread shock at what has emerged.
I've spoken to the boys' father who says he is heartbroken, while Reyaad Khan's mother says she is devastated.
Both of those have appealed for all of the men to come home.
In the video posted by internet accounts linked to militants from the Islamic State of Iraq and the Levant (Isis), Reyaad Khan, who went to Cantonian High School and St David's Catholic College in Cardiff, is seen holding a gun and sitting next to his friend Nasser Muthana.
Nasser Muthana, of Butetown - who has been offered places to study medicine by four universities - appears in the footage, using the name Abu Muthanna al-Yemen and urging others to fight in Syria and Iraq.
His father, Ahmed Muthana, said his son - who he described as quiet, well-educated and intelligent - had left the UK to fight in Syria in November.
The families of the men believe they have been brainwashed and have appealed for them to come home.
It is not the first time fears have been raised about the radicalisation of young Muslims in Cardiff.
Reyaad Khan lived close to the Cardiff men jailed over the London Stock Exchange plot, with the Daily Telegraph reporting that Reyaad Khan grew up in the same street in Riverside as Abdul Miah, one of the ringleaders of the plot.
The Stock Exchange plotters - nine men in total also from London and Stoke-on-Trent - had planned to raise funds for a terrorist camp in Pakistan and recruit Britons to attend.
Sheikh Zane Abdo from the South Wales Islamic Centre in Cardiff, where Nasser Muthana and his brother have prayed in the past but not for years, has also said he believes there is a problem with extremism in Cardiff.
He said he believed "a certain amount of radicalisation" could occur online.
"It very simple, very easy for a person just to click on (it) and become radicalised over a long period of time," he told BBC News.
"The fact that the video they've shown... I guarantee many young people who are susceptible to this kind of message will have watched the video and maybe (be) encouraged to follow in the footsteps of Nasser and his brother.
"A platform has been given to this video which really shouldn't have been given.
"So there's issues around the internet and issues around people who can radicalise, can talk to young people."
He said the pair had been normal teenagers before they went through a "very strange period" when they started expressing "certain views".
Isis grew out of an al-Qaeda-linked organisation in Iraq
Dr Lakhani said there were several reasons why young men may be willing to risk their lives abroad.
"It's really a combination of humanitarian concerns, a feel for having a duty towards their religion, towards their Muslim kin, and some personal reasons as well," he said.
"It's about leaving your formerly mundane and predictable life to search... for brotherhood and some sort of identity, masculinity and action abroad."
Mohammed Sarul Islam, a former Riverside councillor who knows the Khan family, agreed that radicalisation was happening "under people's noses".
He said it was better to try to solve the problem rather than blaming communities or individual organisations.
He added: "The family's only hope is they get any government-level help (to bring their son home).
"The mother is crying her eyes out... all the time she is urging through the media, through whatever source possible, asking him to come back home."
He said the family thought their son had gone to Birmingham for an Islamic conference and were shocked when police said he had left the country.


Making European emissions tests more stringent could make some diesel vehicles "effectively unaffordable", a trade body has warned.

The European Commission is trying to get vehicle makers to agree to bigger cuts in emissions from diesel engines.
The pressure comes in the wake of the Volkswagen emissions scandal.
The European Automobile Manufacturers' Association (ACEA) said car companies needed enough time to implement changes to emissions testing.
Diesel vehicles have been encouraged in many European markets because they can produce less carbon dioxide - a major greenhouse gas - than those with petrol engines.
The trade body said diesel was an important part of meeting future CO2 targets and it was important for the Commission to let manufacturers plan and implement necessary changes.
The VW scandal, in which saw the German car maker admit rigging emissions tests, has put significant pressure on diesel vehicle manufacturers.
Diesel engines emit higher levels of nitrogen oxide and dioxide (NOx) that are harmful to human health. European government officials have set out plans to introduce real-world measurements of NOx emissions rather than rely on laboratory tests.
The new testing regime is due to start early next year, with the results coming into effect in 2017.
However, talks between officials in Brussels last week to discuss the plans are reported to have stalled.
The ACEA said it would continue "to stress the need for a timeline and testing conditions that take into account the technical and economic realities of today's markets".
The trade body added: "Without realistic timeframes and conditions, some diesel models could effectively become unaffordable, forcing manufacturers to withdraw them from sale."
Such a move would hit both consumers and jobs in the automotive sector, it said.


A total of nine youths - including a girl aged 12 - have been charged over a fire in a derelict part of the Royal Cornhill Hospital site in Aberdeen.

Two rooms in the former hospital were affected by the fire on 8 June but no-one was injured.
Police previously said a boy aged 13 had been charged.
A further eight youths - two girls aged 12 and 16, and six boys between 14 and 17 - have also now been charged in connection with wilful fireraising.


Maggie Chapman has been re-elected as co-convener of the Scottish Green Party.

Ms Chapman triumphed over challenger Zara Kitson following a month-long ballot of the party's 9,000 members.
The party has both male and female co-conveners, with Ms Chapman sharing the leadership with Patrick Harvie.
The Aberdeen University rector quit her council seat in Edinburgh in the summer to concentrate on her bid to win a seat at Holyrood in 2016.
Ms Chapman said: "This has been a really exciting election, and I'm really pleased the Scottish Green Party has chosen my vision of a welcoming, socially just Scotland which works for good in the world.
"I congratulate Zara on her campaign, and look forward to working with her and the other candidates to deliver the best yet result for our party in the Holyrood election next year.
"Next year's election is a great opportunity for us to make a really big impact on Scottish politics and to give a voice to the movements that are changing and will change our country and our world."
Mr Harvie, who did not face a contest for the position of male co-convener, added: "I'd like to thank all those who stood for party positions. My congratulations to Maggie on winning the female co-convener contest and I look forward to both Zara and Maggie being elected as MSPs in May."


A dog that mauled a tiny Yorkshire terrier to death outside its home, was "out to kill", its elderly owners said.

Their pet Lacey was being walked on a lead with three other terriers when she was attacked by a black "Alsatian type" dog in Oldbrook, Milton Keynes.
She died after sustaining internal injuries and broken legs. Her owner was bitten as he tried to rescue her, as reported in the MK Citizen.
The owners reported the attack and said police were investigating.
More on this and other stories from Buckinghamshire
Lacey's owner Ron, 75, who did not want to give his surname, said: "I had two of the dogs on leads, and my wife had the other two.
"The dog lunged at my arm and pulled me down to the ground as it tried to get to my dog. It bit me four times."
He said his other three dogs were saved by a passing postman who bundled them into the back of his van.
The incident left him "absolutely terrified" to take his other dogs for walks, he said.
His wife Valerie said she had struggled to leave the house since the incident and was having panic attacks.
"As soon as I open the front door it all comes flooding back. I can't get it out of my head - it will stay with me until the day I die," she said.
"All I can see is Ron walking towards me with her, and bringing her in the house. You could see her intestines... and her legs were ripped off.
"There's no way ever that dog should not a have had a collar on and a lead. That wasn't a little dog-on-dog scrap. That dog was out to kill.
"If it hadn't been for our heroic postman, I think it would have been more dogs," she added.


More patrols are planned for a Lincolnshire town to tackle anti-social behaviour and street drinking.

A Lincolnshire police spokesman said the patrols in Boston town centre were a result of a "surge of complaints" from local residents.
The town's marketplace is one area where street drinkers are causing problems, a police spokesman said.
"The problems are mainly around the Ingram Memorial on the riverside adjacent to the Boston Stump," he said.
PC Martyn Chambers said there would be "no leniency or tolerance" if people threw litter, urinated in the street or used other anti-social behaviour.
"Some of the people have medical as well as alcohol issues as generally the two often go together.
"We have tried to help them, but we have to say enough is enough," he added.
He said the offenders could be moved along under public order legislation.


Boris Johnson has accused David Cameron of a "stitch-up" over the role played by business in the EU referendum.

He said a letter from the boss of Serco to David Cameron suggested "collusion" between business and Downing Street.
The letter mentioned how support for EU membership could be "mobilised" - and also discussed further privatisation of the prison estate.
Mr Cameron, meanwhile, has suggested the head of so-called Islamic State may be pleased with a vote to Leave.
Speaking in London, the prime minister said Abu Bakr al-Baghdadi, the leader of so-called Islamic State in Iraq, "might be happy" in the event of a Leave vote in June, remarks which Mr Johnson said were a "bit too much".
In other EU developments ahead of the 23 June referendum:
Vote Leave has seized upon a leaked letter, published in the Daily Mail, from Rupert Soames - the head of the outsourcing firm Serco - to the prime minister on 8 February, in which he refers to a meeting with Mr Cameron the week before.
Mr Soames, whose brother is the pro-EU Tory MP Nicholas Soames, wrote he was working with Lord Rose - chair of the Britain Stronger in Europe campaign group - and Lord Chadlington, a long-term ally of Mr Cameron's - with a view to contacting some of the UK's largest firms to persuade them to highlight the perceived risks of leaving the EU in annual reports released before the 23 June poll.
"Thank you for a very useful meeting last week," he wrote. "There were two points I thought I might follow up on.
"The first is how to mobilise corporates to look carefully at the risks Brexit represents... All public companies are required to set out in their Annual Report an analysis of key risks. During the Scottish referendum campaign, we managed to garner a lot of publicity as a series of companies formally stated in their annual reports that independence for Scotland was a major risk."
In his letter, Mr Soames also raised the issues of prison reform and the case for greater private sector involvement in the running of prisons. Serco currently operates six adult prisons in the UK and one juvenile training centre.
The letter was written on the same day Mr Cameron made a speech promising the "biggest shake-up of prisons since the Victorian era", including piloting six "reform prisons" to tackle high levels of violence and re-offending.
Vote Leave said the letter showed Downing Street "had been doing deals with businesses to exaggerate the risk of a vote to leave the EU".
Mr Johnson, the former mayor of London who is now a leading Tory Leave campaigner, said it showed the PM's efforts to renegotiate the EU's membership had been the "biggest stitch-up since the Bayeux Tapestry".
"Everybody is allowed to make their point but it is important that we look at what is really going on," he said on a trip to Stafford.
"When you have what looks like collusion between Downing Street and big Remain-supporting businesses. On the surface, it seems to be suggesting that in exchange for support to remain, there is consideration to be given to the exchanging of lavish public sector contracts.
"I think we need to a full explanation of what is going on without delay."
Britain Stronger in Europe said Mr Johnson was "shouting out conspiracy theories" when he had been a strong supporter of Serco while he was in charge of London. It accused him of "stunning hypocrisy" over outsourcing and other EU-related issues.
Both No 10 and Serco said they would not comment on the details of a leaked letter. The company, which had a turnover of Â£3.5bn last year and more than Â£100m in contracts with EU institutions, has said before that leaving the EU would be a risk to its business.
Speaking to business leaders in London, Mr Cameron said they should "feel free" to speak out on either side of the argument and not be cowed by the politicised nature of the debate.
"The British public deserve to hear from business, large and small, about what they think," he said. "I don't want anyone to wake up on 24 June and feel they were not given the facts and the figures."
The Leave campaign, he suggested, was "losing the argument" and there was a "clear consensus" that quitting the EU would be damaging for both the economy and security.
Meanwhile, the CBI has mobilised dozens of businesses to write to employees explaining why they want to remain ahead of the 23 June poll.
Carolyn Fairbairn, the organisation's director general, said the move was "not about telling people how to vote" but rather an effort by "responsible business leaders" to explain to staff the effect Brexit would have on their companies and their livelihoods.
Former British Chambers of Commerce boss John Longworth said the CBI's involvement was an "anti democratic abuse of power" from an organisation which "supported the ERM and the single currency".


Liverpool midfielder Philippe Coutinho has submitted a transfer request, hours after the Premier League club released a statement saying he is not for sale.

Coutinho stated his desire to leave via email. The club rejected the request.
On Wednesday, the Reds rejected a 100 million euros bid (£90m) from Barcelona for the 25-year-old, who is out of Saturday's trip to Watford with injury.
In a statement on Friday, the club's owners said its "definitive stance" was that "no offers will be considered".
Speaking at an earlier news conference previewing the league match at Vicarage Road (12:30 BST kick-off), Liverpool boss Jurgen Klopp said the Brazilian would miss the season opener because of a back problem.
Klopp said he was also a doubt for Tuesday's Champions League play-off first leg at Hoffenheim as he had "not been in training since last Friday".
Coutinho, who scored 14 goals in all competitions last season, signed a new five-year deal in January that did not include a release clause. He joined Liverpool from Inter Milan for £8.5m in 2013.
Barcelona have also had a bid rejected for Borussia Dortmund's 20-year-old forward Ousmane Dembele since they sold Brazil forward Neymar to Paris St-Germain for a world record £200m last week.
The German club confirmed they met Barca representatives but the offer did not meet their valuation of the France international.
BBC Sport's Simon Stone
Less than three weeks before the end of the transfer window, Liverpool now find themselves in a very tricky position. The club are adamant they will not sell - but what about the player?
As I understand it, Coutinho does not want to fall out with Liverpool, or their fans, and spoil what has been an enjoyable four-and-a-half years at Anfield.
However, the brutal truth is Barcelona are currently a more successful club.
Almost as important is the fact that they, and Real Madrid, hold an attraction for most South American players that is difficult to resist, as Liverpool experienced with Luis Suarez.
Little wonder Coutinho is desperate to make the move.
BBC Radio 5 live's Ian Dennis
Liverpool's stance remains the same but this is significant with a change of attitude from the player.
Previously it seemed Coutinho was content to take an amicable approach. However, his request submitted via email is designed to try and force the issue.
The club are adamant that no offers will be considered but what are the repercussions regarding the relationship with Coutinho and the fans now?
Liverpool are resolute he's not for sale and are in a position of strength because he's under contract until 2022.


Colombian police have rescued a US judge who was abducted last week while on holiday in the historic seaside city of Cartagena, officials say.

Judge Benny Osorio, who serves on the Los Angeles Superior Court, was freed on Thursday by an elite anti-kidnapping unit using intelligence information.
The kidnappers were common criminals who had demanded $30,000 (£24,000) for his release, prosecutors say.
Four suspected kidnappers have been arrested and firearms seized.
The head of the Los Angeles Superior Court, Carolyn Kuhl, said she was "relieved" that her fellow judge had been freed. She added that the US state department and the FBI had worked with Colombian authorities to secure his release.
The number of kidnappings has fallen sharply in Colombia as the government has successfully battled rebel groups over the past decade.
A total of 213 people were abducted in the country in 2015, most of them by criminals demanding ransom, official figures show.


Neil Taylor expects Swansea City to be rejuvenated by new boss Bob Bradley.

The 58-year old, who is the first American to manage in the Premier League, succeeded Francesco Guidolin as Swansea boss with the club only outside the relegation zone on goal difference.
"He strives to get the best out of players. The lads have said training has been really good," said Taylor, who has been on Wales duty.
"He looks a really exciting manager. He looks up for it and backs his ability."
Bradley could not have asked for a tougher baptism on Saturday with Arsenal having won seven of their last eight games in all competitions.
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However, left-back Taylor believes former USA national coach Bradley has already galvanised the squad.
"Hopefully from here onwards we can pick up results because that is what matters in the Premier League," he said.
"He looks very motivated and that is great for the players. We can feed off him and we need to use that to pick up results, that is obvious now."
Taylor fell out of favour under former manager Guidolin, starting only one Premier League game this term in which he was substituted before half-time, but he does not see Bradley's appointment as a new beginning for him.
"I will just go back and work the same way I was working under the old manager, that is the way I do things," Taylor said.
"It makes no difference to me, but obviously there will be different ideas.
"There are ups and downs for every footballer, you just stay on a level playing field whether you are up or down. You keep working the same way, things come back around - that is the way football is."
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Swansea are not expected to end their losing run at the Emirates Stadium with in-form Arsenal winning their last five league matches to move up to third place.
But Swansea have an excellent away record against Arsenal having won on three of their five Premier League visits, including a 2-1 win last season.
"It is a tough first game but we don't mind playing that," Taylor said.
"We are hoping we can pick up from where we left off there last season and pick up points. We would be probably written off even if we were in form."
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Do you know someone who inspires people to get involved in playing sport in their community?

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It could be a person who gives up their time to encourage others to take part in sport, be someone who is helping to unearth a champion of the future or maybe they are the ones who keep a local club going.
The BBC Get Inspired Unsung Hero award has been running since 2003 and recognises the remarkable achievements of people throughout the UK.
You can nominate your unsung sporting hero until 23 October and the Welsh winner will be announced at the BBC Cymru Wales Sports Personality of the Year award in December.
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The winner of the BBC Cymru Wales award will represent Wales at the national BBC Sports Personality of the Year ceremony on 18 December.
Grandmothers and working farmers Jane Roberts and Nerys Ellis jointly won the 2015 BBC Wales Get Inspired Sports Unsung Hero award for their work with Llanrwst Swimming Club. Football coach Damien Lindsay from Northern Ireland won last year's national award.
The nomination period for the 2016 awards is now open. You can download this nomination form and send it to the address provided. If you prefer, you can download the Welsh language form.
Please make sure you provide as much relevant information possible to give the judges a good indication of why your nominee deserves to be considered as Unsung Hero for your region.
Please note that the BBC has no control over and is not responsible for the content on external websites. The BBC recommends that you check their privacy policy to find out how they will handle your information.
Panels will meet at BBC Wales, Northern Ireland, Scotland and each of the BBC's 12 English regions, picking one winner from each area.
The overall winner will be selected from those 15 and will be announced during the BBC Sports Personality of the Year programme on Sunday, 18 December in Birmingham.
See the 2016 Get Inspired Unsung Hero Awards terms and conditions to find out everything you need to know. You can also view these terms and conditions in Welsh.
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The closing date for applications is 23:59 BST on Sunday, 23 October.
Please note that the last day we will dispatch posted nomination forms will be Friday, 14 October.
If you have nominated someone before previously, you can nominate them again this year.
There is a continuing need for more unsung heroes in sport in the UK. If you have been inspired by this and want to get involved in helping grassroots sport in your community, visit the Get Inspired guide to volunteering, there is also a dedicated page for coaching.


Two players from Danish club FC Copenhagen have criticised conditions for labourers working on venues for the 2022 World Cup in Qatar.

Tom Hogli and William Kvist were speaking on a video produced by the Danish players' association and published by world union FIFPro.
"That thousands must die to build stadiums has nothing to do with football," Kvist said.
The Qatari government has always rejected claims workers have died.
However, human rights organisation Amnesty International has accused Qatar of abusing World Cup workers, while Hogli said conditions were "cruel".
The BBC spoke to one English construction worker who left the country after two weeks because, in his words, the conditions were "an absolute disgrace".
Other critics have claimed that 1,200 workers have already died and up to 4,000 could perish before the World Cup begins, a figure denied by Qatar.
The country currently employs about 5,100 workers on World Cup sites, a number that will peak at 36,000 by 2018.
Fifa boss Gianni Infantino said last month that the organisation will establish a body to monitor working conditions for labourers at Qatar's World Cup stadiums and insisted the tournament would stay in the Gulf.
We've launched a new BBC Sport newsletter ahead of the Euros and Olympics, bringing all the best stories, features and video right to your inbox. You can sign up here.


The tower tourists call Big Ben glows in the early autumn sunshine. The pavements around Parliament heave with visitors snapping pictures of the mighty clock. From Seoul to Spain it's seen as the symbol of British government. Stable, solid, timeless.
As Orwell described England in 1941.... "it is continuous, it stretches into the future and the past, there is something in it that persists, as in a living creature."
But nothing is the same.
Westminster's politicians are dazed and disorientated. They feel politics as they know it is cracking up. The main parties are scrambling to keep Scotland in the United Kingdom.
The sleepy assumption that separation would never happen has vanished.  If it happens, Westminster will soon lose its 59 Scottish MPs.
The political damage to David Cameron and Ed Miliband would be immense.
If Scotland stays, a shift of new powers from London to Edinburgh is promised. The rest of Britain will be rewired too. It seems inevitable there will be a devolution of power within England. The remaining Scottish MPs in Westminster would surely lose their right to vote on English matters. The so-called West Lothian Question would need to be answered. The constitutional obsessions of political scientists are no longer niche. They're pressing and urgent.
The crack up has been brewing for several years. Not just the decades' long gestation of Scottish separatism. But in the fading confidence of Westminster's politicians.
The expenses scandal of 2009 was memorable not just for the ludicrous receipt-free claims and care-free sense of entitlement to public money. It was memorable too for the raw fury it unleashed among voters.
The public's trust in politicians had been falling for years. For many voters the scandal exposed a vacuity at the heart of British politics and sealed their contempt for politicians.
When UKIP's leader Nigel Farage condemns the Westminster political establishment he echoes a recruiting message of the Yes campaign in Scotland.
There are big differences between the SNP, the Yes movement and UKIP. But both parties are nationalist and both promise a rejection of politics as usual. They're tapping a deep disillusionment with Westminster politics. And they're both posing an electoral nightmare for the three main parties whose memberships have been in sharp decline for years. Together they have fewer members than the RSPB.
As Labour is discovering in Scotland - it isn't possible to mobilise huge blocks of supporters if the party members and foot-soldiers aren't there anymore.
It's not an original observation that Westminster politics has a so-called "professional political class" at its heart - people who were familiar with the ways of Westminster long before they were elected. Voters have sussed this out. Not dogmatic or interested enough to join a political party themselves they find the entrances to politics blocked.
Shrinking political parties remain the gateways to council seats and the green benches. Politicians claim the media plays its part in sowing disillusionment with the difficult business of doing politics.
The referendum has electrified politics in Scotland and prompted profound questions in Westminster.
Is the rise of English nationalism now inevitable or will greater regional devolution extinguish the UKIP surge?
Are we seeing a nationalist reaction to the forces of globalisation? Can political parties as we've known them survive?
How should we be governed and where should power lie? While the main parties panic about Scotland they're also looking anxiously at the future. Everything looks the same but Westminster politics will never be the same again.


A man thought to be the first to drive using a mind-controlled robotic arm has died in an Austrian hospital after a serious car crash.

It is not known whether his bionic arm had any role in causing the accident.
Christian Kandlbauer, 22, was found in the wreckage of his specially-adapted Subaru on Tuesday.
Late on Thursday he was pronounced brain-dead in intensive care at the Graz hospital and his life support was switched off.
Mr Kandlbauer lost both of his arms four years ago, after being shocked by 20,000 volts.
He was fitted with a mind-controlled robotic arm by the medical technology company Otto Bock Healthcare, which said it was the first project of its kind in Europe.
Using both his left and right arm - which was a normal prosthetic limb - he was able to pass his driving test in a specially converted car.
On Tuesday he was found by a lorry driver who came across his burning car on a road near Bad Waltersdorf in south-east Austria.
The driver managed to put out the flames, but it needed firefighters to extract Mr Kandlbauer from the mangled wreckage.
He had been interviewed by the BBC about his revolutionary limb earlier this year.
"I feel very happy," he said at the time. "It is like my earlier arm - I feel that my arm is a part of my body."
He had returned to work as a warehouse clerk at the garage that once employed him as a mechanic.
He said he was grateful that he had the freedom to get on with his life.


Voters appear to want more powers for the Scottish Parliament - beyond the proposals currently on offer, according to a new poll commissioned by BBC Scotland.

However, the nation seems divided over whether there should be another referendum on independence in the near future.
Pollsters Ipsos Mori asked voters to give a score out of 10 to a range of policies which could be implemented by the next UK government.
A ranking of one meant it should not be implemented, while 10 meant it should be implemented immediately.
Ipsos Mori surveyed more than 1,000 adults between 19 and 25 March.
Click here to see the full results.
Many of those questioned seemed to favour going beyond the Smith Commission proposals, which suggested that Holyrood should control income tax rates and bands as well as some welfare benefits.
Give Holyrood full control of income tax 6.8
Increase top rate of tax to 50p 7.2
Increase minimum wage to £7.85 8.2
The most popular of the policy statements in this category was that of giving Holyrood the power to increase benefits and old age pensions, which scored 7.3 out of 10 on the scale.
Close behind was the notion that the Scottish Parliament should have full control of welfare benefits, with a score of 7.1.
Scots appear to place a greater emphasis on embedding and extending powers at Holyrood parliament than on holding a second independence referendum.
When asked to give a score of between 1 and 10, where 10 is an important priority and should be done quickly, each of the four issues relating to additional powers for the Scottish Parliament achieved high average scores.
Giving Holyrood power to increase benefits and pensions achieved an average score of 7.3 out of 10, a little higher than devolving full control of welfare benefits (7.1), full control of income tax (6.8) and full control of all policy other than defence and foreign affairs (6.5).
Interestingly, analysis shows that, for each of these issues, support is higher among groups who are more likely to have voted 'Yes' in last year's referendum.
Read Mark's analysis of the poll.
The idea that Holyrood should have full control of income tax was given a score of 6.8.
Still popular, but a bit further down the ranking with a score of 6.5, was the suggestion that Holyrood should control all areas of policy apart from defence and foreign affairs - what most analysts call full fiscal autonomy.
The results of the poll suggested that voters would rather have a referendum on whether or not to leave the European Union than another referendum on Scottish independence.
Voters gave the policy statement "hold another referendum on Scottish independence within the next five years" a score of 5.6 out of 10.
Cap amount paid in welfare to a household 6.3
Limit numbers coming to live in UK 6.3
Give Holyrood full control of welfare 7.1
The policy statement "hold a referendum to ask people whether they wish to stay in or leave the European Union" was slightly more popular, with a score of 6.1 out of 10.
The idea of stopping immigrants from the rest of the European Union from claiming welfare benefits until they have been in the UK for four years scored 6.8.
The policy of putting a limit on the number of people coming to live in the UK was less popular, with a score of 6.3.
As ever, how much the next government should spend and how much it should tax is proving to be one of the central issues of the UK general election campaign.
And there seems to be little doubt as to where the majority of Scots stand on this issue, at least if the evidence of BBC Scotland's issues poll is to be believed.
The poll strongly suggests that:
Read Professor Curtice's analysis of the poll
Increasing the amount spent on the armed forces was scored 6.2.
However, renewing and upgrading the Trident nuclear deterrent, came joint last in the poll of priorities, with a score of 4.0.
The poll also indicated some support for bringing the railways back into public ownership - this scored 6.5 out of 10.
"Ensuring authorities cannot access personal data unless an individual is suspected of taking part in an illegal activity" was among the most popular policy statements tested, with a score of 7.6.
What are the top issues for each political party at the 2015 general election?
Policy guide: Where the parties stand


Dosing farm animals with antibiotics increases greenhouse gas emissions from cow dung, research suggests.

Scientists say the drugs boost methane production in cowpats - apparently by favouring antibiotic-resistant, methane-producing organisms in the gut.
Antibiotics also change the microbes which inhabit dung beetles, although apparently with no adverse effects.
The researchers say it’s proof that antibiotic use on farms has unintended, cascading effects on the environment.
For the new paper, in Proceedings of the Royal Society B, researchers followed the trail of antibiotics in cattle and discovered, perhaps unsurprisingly, that said trail did not stop at the cow’s rear end.
The antibiotics changed the microbes in the digestive system of dung beetles, which are vital for cycling carbon and improving soil. The beetles, though, did not appear to be damaged.
By contrast, clear harm was measured in the antibiotic-contaminated cowpats themselves, which produced 1.8 times more methane – a powerful greenhouse gas.
This was a surprise, as previous studies have found little or no impact on the dung.
One of the authors, Tobin Hammer from the University of Colorado, told BBC News that some key research questions remained unanswered.
He said: “Most methane generated by cattle is actually released as burps, and we think that antibiotics are likely to increase burped methane as well - but in this study we weren't able to measure that directly.
“A second unknown is how generalisable the findings are, across different types of antibiotics.
“Lastly, we don't know whether, in terms of environmental impact of antibiotics, the problem of methane emissions is outweighed by the benefits of increasing feed efficiency and treating disease.”
Prof Tim Morris, from the University of Nottingham School of Veterinary Medicine and Science, commented: “Antibiotic misuse needs curbing for many reasons, and the findings in this paper are important where the drugs are being misused.
“However, without undue complacency, these findings should neither distract from more pressing priorities to curb antibiotic use, nor be inappropriately misused on wider questions over agriculture in the UK.”
So for now, the paper is a curiosity rather than a bombshell – although it may be another knock for farmers, who have been blamed recently for fuelling antibiotic resistance in humans, increasing air pollution, and fuelling climate change.
Follow Roger on Twitter


China has urged the Philippines to remove a ship which serves as a military outpost in the disputed South China Sea.

The Philippines said Tuesday it would repair the Sierra Madre which is at a shoal also claimed by China.
A Reuters report said the Philippines also plans to revive a former US naval base in Subic Bay.
China has been reclaiming land and building facilities on reefs in the area angering its neighbours.
The US has called on all claimants to halt such activities which have ratcheted up tensions in the region.
The Philippines has taken China to a United Nations tribunal for arbitration over their overlapping claims.
China's foreign ministry spokesman Hua Chunying said on Wednesday that the Philippines "aggravates the situation by carrying out illegal activities" on the Sierra Madre at the Second Thomas Shoal.
She called on the South East Asian country to tow away the ship.
"The Philippines' breach of its own promise to the international community discloses its hypocrisy and duplicity, and stands as another example that the Philippines is the real trouble-maker and rule-breaker in the region," she said.
The Philippines has said it is repairing the Sierra Madre, which was stranded on the shoal in 1999 to mark the country's claim, to provide for its small group of marines stationed on the ship.
"Maintenance repair is being done to ensure the vessel's minimum habitability," Philippine Navy spokesman Col Edgard Arevalo told AFP news agency.
A BBC report in September 2014 found the World War Two-era ship in bad condition and crumbling in some places from rust.
Meanwhile a Reuters report on Thursday cited officials as saying the Philippines plans to revive a naval base at Subic Bay, which used to be operated by the US military and has since been incorporated into a commercial zone.
Defence Undersecretary Pio Lorenzo Batino told the wire agency that the military had leased the facility from the zone's operator since May.
New fighter jets and two navy frigates are expected to be stationed there from early next year.
The bay is only 145 nautical miles (270km) from Scarborough Shoal, which is claimed by both China and the Philippines.
Aside from those two countries, Brunei, Malaysia, Vietnam and Taiwan also have competing claims over various islands, reefs and shoals in the region.
China claims ownership over a large part of the South China Sea, and has been spotted reclaiming land and building facilities on various reefs in recent months.
It has rebuffed international calls to stop such activities, which it says are within its maritime rights and for civilian purposes.


Premier League sponsors and broadcasters have been told to pull out of football unless progress is made in providing facilities for disabled fans.

Lord Holmes of Richmond, Britain's most successful Paralympic swimmer, made the call during the second reading of The Accessible Sports Grounds Bill.
He told the House of Lords: "What we see is nothing short of shambolic."
The move comes after a BBC Sport investigation found top-flight clubs discriminated against disabled fans.
Only current three top-flight stadiums, Swansea, Bournemouth and Leicester, provided the required number of wheelchair spaces, while the BBC survey in March 2014 revealed eight failed to offer even half of what they should under national guidelines.
Lord Holmes added: "Today, I'm going to write to the sponsors of the Premier League and the broadcast partners to suggest to them that if there isn't considerable progress - so far I think we can describe it as glacial progress - in this area they should consider their relationship with football and how that fits with their ethical state in the market."
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He highlighted abuse against disabled fans at Liverpool and an 80-year-old man at Manchester United who had his walking stick taken off him by stewards.
A Chelsea fan was told to wait until 2022 for the club's new stadium to offer more seats, the Conservative peer added.
The Accessible Sports Grounds Bill, moved by Labour's Lord Faulkner of Worcester, would give local authorities the power to refuse to issue a safety certificate to a sports ground which does not comply with accessible stadia guidelines.
Elliot Dunster, head of policy, research and public affairs at disability charity Scope, said: "Many disabled football fans are being let down by Premier League clubs.
"Football is our national game. Clubs need to do so much more to provide a level playing field so disabled fans can be part of it."


Winger Tim Visser insists Scotland are only thinking about beating South Africa and rejects the notion that the side is weakened by 10 changes.

The Scots can reach the World Cup quarter-finals with a victory at St James' Park on Saturday.
"In a World Cup you don't go out half-hearted to get through to the next game," said Visser.
"I don't think any coach puts out a second string squad to do that against South Africa."
Stuart Hogg continues at full-back and will be the only player to start the first three Pool B matches for Scotland.
Fly-half Finn Russell is absent through injury and flanker John Hardie is not being risked after suffering a head knock in the opening win over Japan.
Impressive performers Sean Maitland and Mark Bennett are left out, while experienced front-row duo Ross Ford and Alasdair Dickinson are on the bench.
Gordon Reid, Richie Vernon, Sam Hidalgo-Clyne and Blair Cowan, who was called up in place of the injured Grant Gilchrist, are all in the match-day 22 for the first time at the tournament.
"We've had three games in 10 days and the squad has been selected with 31 players to do the job," added Visser, a try-scorer in the win over USA.
"We're expecting everyone to perform and we're going out to win the game tomorrow."
Scotland top the group after two bonus-point victories, while the Springboks recovered from a surprise loss against Japan to demolish Samoa.
The big-hitting Pacific Islanders are Scotland's final opponents before the knockout phase of the tournament.
But Visser is only focused on the task ahead in Newcastle.
"South Africa are a physical team and that generally comes out in the forwards because that's the way they like to play. But they have quality throughout the team," added the 28-year-old.
"They've got a world class set of backs and some young players have come through really well recently.
"They have a world class finisher in Bryan Habana as well, so they are incredibly dangerous. We'll keep an eye on Willie le Roux at the back as well - he's a handy player."
South Africa: Willie le Roux; JP Pietersen, Jesse Kriel, Damian de Allende, Bryan Habana; Handre Pollard, Fourie du Preez (captain); Tendai Mtawarira, Bismarck du Plessis, Jannie du Plessis; Eben Etzebeth, Lood de Jager; Francois Louw, Schalk Burger, Duane Vermeulen.
Replacements: Adriaan Strauss, Trevor Nyakane, Frans Malherbe, Pieter-Steph du Toit, Willem Alberts, Ruan Pienaar, Pat Lambie, Jan Serfontein.
Scotland: Stuart Hogg, Tommy Seymour, Richie Vernon, Matt Scott, Tim Visser, Duncan Weir, Greig Laidlaw, (capt), Gordon Reid, Fraser Brown, Willem Nel, Richie Gray, Jonny Gray, Josh Strauss, Blair Cowan, David Denton.
Replacements: Ross Ford, Alasdair Dickinson, Jon Welsh, Tim Swinson, Ryan Wilson, Sam Hidalgo-Clyne, Peter Horne, Sean Lamont.


Exeter City sealed a huge win in their quest for the League Two play-offs with two goals in stoppage time sealing victory over Morecambe.

Chances were few and far between in a rather turgid first half with Exeter missing the best of those.
However, the Grecians lifted after half-time and took the lead on 47 minutes when Ryan Harley's corner fell to David Wheeler and his scuffed shot somehow squeezed under Daniel Nizic and rolled over the line.
Joel Grant then missed a glorious chance when he blazed horribly wide on 62 minutes, but Morecambe equalised when substitute Kevin Ellison smashed a stunning volley across goal and into the top corner from 15 yards.
Exeter, however, went on to win it in stoppage time when substitute Reuben Reid, fouled in the penalty box by Michael Rose, picked himself off the floor to smash the spot-kick into the bottom corner.
Fellow substitute Liam McAlinden then added a third when Exeter struck on the counter attack as he waltzed across the penalty box before planting a shot into the bottom corner.
The win sees Exeter move up to fifth in the table, three points clear of Mansfield in eighth spot with two games to go.
Match report supplied by the Press Association.
Match ends, Exeter City 3, Morecambe 1.
Second Half ends, Exeter City 3, Morecambe 1.
Goal!  Exeter City 3, Morecambe 1. Liam McAlinden (Exeter City) left footed shot from the centre of the box to the bottom left corner.
Hand ball by Kevin Ellison (Morecambe).
Goal!  Exeter City 2, Morecambe 1. Reuben Reid (Exeter City) converts the penalty with a right footed shot to the bottom left corner.
Penalty Exeter City. Reuben Reid draws a foul in the penalty area.
Penalty conceded by Michael Rose (Morecambe) after a foul in the penalty area.
Corner,  Morecambe. Conceded by Pierce Sweeney.
Substitution, Exeter City. Liam McAlinden replaces Ollie Watkins.
Troy Brown (Exeter City) is shown the yellow card for a bad foul.
Rhys Turner (Morecambe) wins a free kick in the attacking half.
Foul by Troy Brown (Exeter City).
Substitution, Exeter City. Lee Holmes replaces Joel Grant.
Ryan Edwards (Morecambe) wins a free kick in the defensive half.
Foul by Troy Brown (Exeter City).
Pierce Sweeney (Exeter City) is shown the yellow card for a bad foul.
Kevin Ellison (Morecambe) wins a free kick on the left wing.
Foul by Pierce Sweeney (Exeter City).
Michael Rose (Morecambe) wins a free kick in the attacking half.
Foul by Joel Grant (Exeter City).
Corner,  Morecambe. Conceded by Jordan Moore-Taylor.
Corner,  Morecambe. Conceded by Pierce Sweeney.
Attempt saved. Reuben Reid (Exeter City) header from the centre of the box is saved in the bottom right corner.
Substitution, Morecambe. Rhys Turner replaces Paul Mullin.
Corner,  Exeter City. Conceded by Aaron McGowan.
Substitution, Exeter City. Reuben Reid replaces Ethan Ampadu.
Delay in match Paul Mullin (Morecambe) because of an injury.
Attempt blocked. David Wheeler (Exeter City) left footed shot from very close range is blocked.
Back pass by Danijel Nizic (Morecambe).
(Exeter City) wins a free kick in the defensive half.
Lee Molyneux (Morecambe) is shown the yellow card for a bad foul.
Jordan Moore-Taylor (Exeter City) wins a free kick on the left wing.
Foul by Lee Molyneux (Morecambe).
Foul by Kevin Ellison (Morecambe).
Ethan Ampadu (Exeter City) wins a free kick in the attacking half.
Dean Winnard (Morecambe) wins a free kick in the attacking half.
Foul by David Wheeler (Exeter City).
Aaron McGowan (Morecambe) wins a free kick on the right wing.
Foul by Jake Taylor (Exeter City).
Attempt missed. Lee Molyneux (Morecambe) right footed shot from the right side of the box is close, but misses to the left.


Former Scottish First Minister Alex Salmond is to host a live weekly radio phone-in show on a London-based station.

Broadcaster LBC said "no topic will be off limits" as listeners call, text, tweet or email the SNP MP directly.
It has released a promotional video showing Mr Salmond reading offensive tweets about himself.
Fellow politicians Boris Johnson and Nigel Farage already host regular phone-ins on LBC.
Former Lib Dem leader Nick Clegg also answered questions every week for two years until the last general election.
Mr Salmond's show will be broadcast live at 16:00 every Wednesday from 13 January.
In a broadcast clip ahead of his first show, he revealed that a dark chocolate Bounty "is the bar for me" in response to a comment that "if Alex Salmond was chocolate he would be dark and bitter".
Mr Salmond also read out a tweet from another listener who quipped that the former first minister has "Fuzzy-Felt eyebrows".
The former SNP leader said: "It is a great pleasure to be joining LBC for my first ever radio show.
"When I was first minister of Scotland, there were times when I had to bite my tongue. However, now unburdened from office, I can shoot straight from the hip.
"I am looking forward to discussing all of the issues and taking calls from every corner of these islands. It's going to be honest, straight talking with a bit of fun thrown in."
Mr Salmond resigned as first minister and SNP leader after the 2014 Scottish independence referendum but has retained a high-profile role in politics, returning to the House of Commons as MP for Gordon in last year's general election.
LBC managing editor James Rea said: "Alex Salmond is one of the most outspoken and straight-talking politicians, with in-depth knowledge of Westminster and Scottish politics, and we look forward to him joining our powerful line-up this year."
But Scottish Conservative deputy leader Jackson Carlaw predicted: "With his pledge to shoot from the hip, Nicola Sturgeon will be listening from behind the sofa in fear of what embarrassment her predecessor can now cause on a weekly basis."