David Cameron is to shelve plans to call a House of Commons vote to approve British airstrikes against Islamic State (Isis) targets in Syria in a belief that he has failed to win over enough Labour MPs and a recognition that Russia’s military intervention has complicated the picture.

Downing Street has decided that RAF involvement in coalition airstrikes against Isis targets should not be extended from Iraq. There are fears that the prime minister would be weakened on the world stage by a second parliamentary defeat over military action in Syria.

Ministers had been discussing a potential Commons motion with Labour MPs as recently as 10 days ago, but the government has undergone a change of heart after failing to win the support of sufficient Labour MPs to be confident that it can overcome what is likely to be a sizeable Conservative rebellion.

It is estimated that 20 to 30 Labour MPs would be prepared to vote in favour of strikes – about the same number of Tory MPs who would rebel against the prime minister.

The Tories’ parliamentary majority of 17 means that, on paper at least, the prime minister could still prevail if the number of rebel Labour and Tory MPs cancelled each other out. But Cameron, who was badly burned after he failed in his attempts to win parliamentary approval for separate airstrikes against Bashar al-Assad in August 2013, is likely to be nervous about holding a vote when the numbers are so tight. He has previously said that he would only table a vote if there was a “genuine consensus” on the issue.

The change of heart in Downing Street has emerged as the Commons foreign affairs select committee expressed scepticism about the value of extending UK military action to Syria. The committee, chaired by the Conservative MP Crispin Blunt, concluded in a report published on Tuesday that any benefits from such action, such as the policy being welcomed by the US, were heavily outweighed by the negatives.

The report raised questions about the relevancy of RAF airstrikes in Syria. “Whilst our witnesses believed that a decision to extend airstrikes into Syria would be welcomed by ([the US-led) ] coalition allies, they did not consider it would have anything other than a marginal effect.”

It concluded the government has so far failed to make the case for intervention. The focus on extending airstrikes is described in the report as “a distraction” from the bigger issue of resolving the conflict in Syria..

The 28-page report concluded: “We believe that there should be no extension of British military action into Syria unless there is a coherent international strategy that has a realistic chance of defeating Isil (Islamic State of Iraq and the Levant) and of ending the civil war in Syria. In the absence of such a strategy, taking action to meet the desire to do something is still incoherent.”

The report raised questions about the relevancy of RAF airstrikes in Syria. “Whilst our witnesses believed that a decision to extend airstrikes into Syria would be welcomed by (the US-led) coalition allies, they did not consider it would have anything other than a marginal effect.”

The 13-strong coalition has conducted 5,000 airstrikes in Iraq and 2,500 in Syria. The US accounted for 70% of those in Iraq and 95% in Syria. The UK, which has eight Tornados involved, has conducted 300 of the strikes in Iraq.

Other questions raised in the report include the legality of such military action and the danger of further complicating the situation on the ground in Syria, which has been made even more problematic by the the intervention of Russia.

Stephen Gethins, SNP MP for North East Fife, who is a member of the committee, said: “After taking evidence from a range of sources including former military personnel, academics, Syrian groups and a range of experts it is clear that the case for war has not been made.”

Ministers had indicated in the early summer that the government would seek to win parliamentary approval for an extension of UK airstrikes against Isis targets from Iraq to Syria. The defence secretary, Michael Fallon, said in July that there was “an illogicality” about striking Isis targets in Iraq but not in Syria.

The prime minister had been trying to win over Labour MPs in favour of action in Syria after the election as party leader of Jeremy Corbyn, who has spoken out against the proposed airstrikes.

Labour MPs seen as supportive were asked whether they could endorse a parliamentary motion that would make it clear that RAF involvement in Syria would be limited to assuming a proportion of the coalition airstrikes in a corridor from Iraq up to the Syrian city of Raqqa, the capital of Isis. The UK currently provides surveillance and intelligence support for the strikes undertaken by the US.

One Whitehall source said: “It is very unlikely the PM will go for vote at the moment. It looks like there is not the certainty of support from Labour and Russia’s intervention in Syria has complicated the picture.”

A leading Labour supporter of airstrikes said he was gloomy about the prospects of greater British involvement. John Woodcock, the Labour MP for Barrow and Furness, said: “The government’s tactics about parliament are just putting the cart before the horse. They are putting out feelers to divine what parliament would accept.

“What would ultimately win more support would be to decide on a strategy that could make a difference and then spend the time setting out the case and allowing people to question that strategy ahead of a vote.”

A vote to support a widening of the airstrikes may not technically count as a Labour rebellion because John McDonnell, the shadow chancellor, has spoken of offering MPs a free vote. But Labour MPs may be nervous about taking a different view on such a sensitive and high-profile issue to Corbyn when a large number of MPs will face reselection battles in redrawn parliamentary boundaries.

A Downing Street source said: “The prime minister’s position hasn’t changed. He’s consistently said that we would only go back to the house on this issue if there was clear consensus and that remains the case.

“Meanwhile, the government continues to work to bring the conflict to an end in Syria and we are working closely with our allies to inject greater momentum into efforts to find a political solution, which we’ve always said will be the way to bring this war to an end and give Syria hope for the future.”



The challenge for the prime minister of relying on Labour MPs was highlighted when Catherine West, a shadow foreign office minister, said that the party would consult the Stop the War coalition before agreeing to any extension of the strikes. West told a Stop the War coalition meeting at Westminster: “If that proposal does come forward, then we will need to speak to you and talk to you about what your view on that is.”



