Michael Fallon calls on MPs to consider supporting British airstrikes in Syria

But Julian Lewis, chair of the Defence select committee, said it was impossible to intervene in Syria without helping either the Islamic terrorists in the north of the country or President Assad’s regime.

On Wednesday he said “there is an illogicality about not being able” to strike IS positions in Syria, because the militants “don’t differentiate between Syria and Iraq”.

The death of 30 Britons in an Islamist attack in Tunisia last week has changed the calculus, prompting Cameron, via his spokeswoman, to ask lawmakers to start thinking about whether they would back wider action. She said Cameron “has long thought that ISIL poses a threat to Britain and needs to be destroyed in Syria as well as Iraq”.

“Any proposals that the Government bring forward which will help tackle the growing horror of Isil, of course we will look at them very seriously”.

Shadow defence secretary Vernon Coaker said ministers needed to demonstrate that any further United Kingdom intervention had the support of other countries in the region as well as a proper legal basis.

But he added: “This is of course though a new parliament and it is for all members to consider how best to tackle Isil, an evil caliphate that does not respect state boundaries”.

Ministers wouldn’t risk losing another vote on Syria unless they knew they had the support of the Labour Party.

Another fact is that despite the many acts of terrorism and violence that take place in Iraq and Syria, they don’t resonate as much as the ones committed elsewhere, such as the ones carried out last Friday by individuals in their early twenties who escaped the state radar.

Fallon told the pre-arranged Commons debate on global security that Isis was directed and led from northern Syria and directing attacks in other countries.

Britain’s Parliament voted in September to attack militants in Iraq, but not Syria.

Cameron has repeatedly said he would seek parliament’s approval to conduct any air strikes inside Syria.

He made clear however that the Government wouldn’t stage a new vote of MPs unless it was clear there was “some consensus” across the House for widening the existing RAF operations against IS in Iraq.

The prime minister’s spokeswoman, Helen Bower, said there would be no immediate decision. We are not providing very numerous aircraft.

Speaking to Sky News Col Bob Stewart, the ex- United Nations Commander in Bosnia, said he would be in favour of the UK taking action in Syria because that is where the key strategic targets are.

He will insist that there is no legal barrier to British military attacks and point out that both the Canadian and Jordanian air forces have already attacked Syrian targets.

“At the end of the day, we need credible, moderate partners on the ground”, Joint Chiefs of Staff Chairman Gen. Martin Dempsey said at the same briefing regarding the train and equip program in Syria.