The Prime Minister was due to hold late-night talks with Iraqi PM Haider al-Abadi yesterday which could see a formal request from Baghdad for Britain to follow the United States in bombing the extremist organisation’s forces.

Defence Secretary Michael Fallon said yesterday that the RAF could join air strikes against Isis in Iraq if Parliament authorised it.

But he hinted that unlike the US, Britain would probably not launch attacks on Isis in Syria.

Although Isis controls a continuous territory straddling the Syria-Iraqi border, Western hostility to the Bashar al-Assad government in Damascus means Paris and London are reluctant to help it defeat the group.

Ahead of a shadow cabinet meeting to discuss Labour’s response to any government bid to bomb Isis, Ed Miliband said he would consider requests from Mr Cameron on the issue “very seriously.”