Theresa May is under increasing pressure from her own backbenchers to cancel Monday’s business in parliament to make time for a full-scale debate and vote on intervention in Syria.

“The government owes it to parliament to come and explain,” said Bob Seely, the Isle of Wight Conservative MP who says he is sceptical about intervention. “Articulating their case in a chamber full of critical voices is good for the government. If it can’t, then maybe it shouldn’t be doing it.”

Tory backbenchers fear that if May approves a military strike without parliamentary support and it goes wrong, perhaps through civilian casualties or the loss of a British plane, she could jeopardise her minority government.

Dominic Grieve, the former attorney general, said on Friday: “If it all goes terribly wrong then the government will be in difficulties. It will then have chucked at it that it hasn’t consulted parliament.



“The pressure on government to hold a debate in government time is going to become overwhelming. It has to be reasonable and take parliament into its confidence. Parliament can’t just be left sitting on the sidelines.”

The veteran Tory MP Ken Clarke is also demanding a debate.



Although the government is entitled under the royal prerogative to decide to go to war, since the debate on Iraq in 2003 there has been a convention that no administration would embark on military action without getting the support of parliament.

Grieve said there was no legal basis for a punitive raid to deter the Syrian regime from repeating what he called its “flagrant breach” of the international convention banning chemical weapons – except under the doctrine of humanitarian necessity. That is the UN convention on the responsibility to protect, agreed in 2005, which was the basis of Cameron’s unsuccessful appeal to parliament over Syrian intervention in 2013.

Some parliamentarians say the contentious status of international law, if combined with the lack of parliamentary support, would seriously weaken May.

The Liberal Democrats’ defence spokesman and former leader, Menzies Campbell, said: “What if she loses a plane? Or something else goes wrong? She really will be in a very difficult position. I don’t see how she could survive that.”

Downing Street is said to be confident that it could win a vote on intervention, unlike Cameron, who wanted to take military action that was “legal, proportionate and focused on saving lives”.

But No 10 is understood to be concerned that it cannot delay if the US and France are ready to act in the wake of the chemical attack on Douma last weekend in which as many as 75 people, including children, may have died.

If the government does not offer a debate, both Labour and the Scottish National party are planning to demand that the Speaker, John Bercow, grants one on Tuesday. The Commons business this week is dominated by one small piece of legislation to do with road safety.