David Cameron to unveil plan for air strikes on Isis in Syria within days

Poll reveals more than half the public believes there are circumstances in which ground forces should be sent to attack

Action plan: The Prime Minister will attend a ‘war summit’ in Paris on Monday (Rex)

David Cameron is set to unveil his war plan for British air strikes in Syria within days, as Downing Street rushes to join French-led attacks on Isis.

The Prime Minister is expected to publish a “comprehensive strategy ... by the end of the week” for defeating Isis, with MPs expecting a vote to authorise RAF bombing raids early next month before Parliament breaks up for Christmas on 17 December.

Mr Cameron will fly to Paris for a war summit with President François Hollande tomorrow, as Parliament and the public appear to rally behind British involvement in an international coalition.

The PM’s confidence of winning a vote was bolstered after the unanimous backing of a UN Security Council resolution late on Friday night, authorising “all necessary measures” to defeat Isis.

There are growing signs that support for action is growing. Crispin Blunt, the chairman of the influential Commons Foreign Affairs Committee (FAC), has now issued a warning to wavering MPs that there could not be “a clearer necessity for using force”.

Latest poll findings reveal that more than half the public now believe there are circumstances in which British ground forces should be sent to attack Isis; up to 70 Labour MPs could back the Prime Minister’s plan for air strikes in Syria, and party whips are convinced there are not enough MPs opposed to action to stop Mr Cameron ordering RAF planes across the border from Iraq into Syria.

In further signs that parliamentary opposition to air strikes is fracturing, the shadow Chancellor, John McDonnell – a close ally of Labour leader Jeremy Corbyn, who is against such strikes – called for a “free vote” to allow Labour MPs to back action without defying party orders.

However, Sir Michael Graydon, former head of the RAF, who masterminded the “safe havens” policy in Iraq and Bosnia in the 1990s, writing in The Independent on Sunday, calls for a UN-backed plan to establish a humanitarian corridor and safe havens to staunch the flow of refugees from Syria.

A ComRes poll in the IoS found half of the public now agree the UK should take part in air strikes against Isis, even without UN approval. Two thirds say that killing British citizens in Syria is justified if the security services say they have joined Isis. Just one in four Britons believes there are no circumstances under which British troops should be sent to fight a ground war against Isis.

Mr Corbyn has remained defiant, warning against “external intervention” in Syria. He said Labour would “consider the proposals the Government brings forward”.

The PM will outline his plan in response to an FAC report earlier this month which criticised the Government’s failure to produce a plan to defeat Isis and questioned whether UK action would make any difference. Mr Blunt said there was “no reason” now why Mr Cameron should not be able to win a vote authorising air strikes. He said military action was needed to wrestle territory from the Isis “lunatics”, adding: “We can’t escape this, we have got to do it. We can’t live with these people, they are our enemies. They are at war with us.”

The Tory MP – a former army captain – said the Isis ideology was “so appalling” it had to be defeated. “It’s a nihilistic death-cult ... The longer you leave this cancer kicking round in control of territory, the bigger [the threat] you are going to have to face.” The MP – who came out as gay in 2010 – added: “You cannot get a clearer necessity for using force than IS. People like me get thrown off tall buildings.”

Asked if the prospect of military action before Christmas was off the table, Mr Blunt replied: “No, no, no – it’s all about the politics now.”

Mr Cameron’s case was getting “easier every day” because of this month’s peace talks in Vienna, which agreed that the Syrian government and opposition forces should gather together no later than 1 January, with elections 18 months later.

No 10 last night played down suggestions a Commons vote on military action was imminent. A senior Government source said: “The worst thing would be to have a vote that we lost. We will only proceed if we are confident we can get this through. We are not pencilling in dates.”

But the source added that if Mr Cameron was sure he was going to win he would move very quickly.

The scale of the threat became even more apparent as it emerged MPs have been warned to be ready to “barricade” themselves in their offices in the event of a marauding terror attack on Parliament following events in Paris and Mali. Security has been stepped up around the parliamentary estate, and extra firearms officers ordered on patrol. But MPs were left furious after an IT glitch meant many did not receive the emergency warning issued on Monday. A second message had to be sent out days later because of a “technical error”.