Opposition leaders have urged Theresa May not to rush to attack Bashar al-Assad’s forces in Syria if she wins the election, after it emerged the government is considering holding a swift vote on military action this summer.
May could have a large majority if she gains Tory MPs at the election, making it more difficult for her own backbench rebels, Labour and other parties to stop her pushing through a vote for military action.
The Liberal Democrat leader, Tim Farron, said it was deeply worrying that May “would back military intervention against Assad in Syria outside of a wider diplomatic strategy and without UN backing”.
He said Donald Trump’s bombing of Syrian regime assets last month was a proportionate response, and the use of chemical weapons was indefensible, but it was wrong to have gone ahead “unilaterally, without allies, outside of a wider strategy”.
“May would be wise not to use Syria as a campaign tool in this election. This would come across as calculating, unconsidered, and without the best interest of the Syrian people at heart.”
Downing Street has not confirmed it wants to hold a vote but a Whitehall source indicated overnight that May wanted Commons backing in order to have the freedom to join the US in airstrikes against the forces of Assad, the Syrian president, in the event of another chemical attack on the rebels.
The Labour leader, Jeremy Corbyn, a longstanding anti-war campaigner, warned May last month against unilateral military action in Syria. “We don’t need unilateral action. We need to work through the UN but, above all, we need to bend ourselves totally to getting a political settlement in Syria,” he said.
Conservative opponents of military action in Syria are reluctant to speak against the plan on the day of the local elections and in the middle of a general election campaign. But two Tories who are expected to be re-elected as MPs told the Guardian their opposition to strikes on the regime in 2013 still stood.
David Davis, now the Brexit secretary, Julian Lewis, the chair of the Commons defence committee, and Crispin Blunt, the chair of the Commons foreign affairs committee, were among the 30 Conservative MPs to rebel against David Cameron’s motion at the time.
Other former rebels however, including Andrew Tyrie, Sir Richard Shepherd, Sir Peter Tapsell and Andrew Turner, will no longer be in the Commons if a post-election vote is held.
The UK is keen to line up fully alongside the US. It is already engaged alongside its American counterparts in military action in both Syria and Iraq against Islamic State, but has not joined in the airstrikes against Assad’s forces.
Russia, which is backing Assad, is said to be seeking new “safe zones” in Syria after talks with the US and Turkey.
Caroline Lucas, the joint leader of the Greens, called on May to come clean about her ambitions. “If Theresa May is planning further military action in Syria then she should come clean with voters and lay out her plan,” she said. “People deserve a say on foreign policy and any attempt to wait until after the election to signal intentions in Syria is simply wrong.
“Parliament is united in horror at the carnage in Syria and the electorate deserve a chance to scrutinise how MPs from all sides will act on the issue if elected.”