Senior parliamentarians and government officials in Britain believe it is highly unlikely that Britain will transfer arms to Syrian militants at some future date because they believe Cameron has lost the political support needed to make such a move.

For many months, Britain’s prime minister has been the most forward-leaning of western leaders in arguing that militants fighting Syrian President Bashar al-Assad’s government may soon need arms from the west.

Last week, Cameron’s position received strong support from the Obama administration in the US, which finally announced that it would transfer arms to the terrorist groups.

However, any attempt by the UK to support such a move is now so firmly opposed by Mr Cameron’s own Conservative MPs that he would be unlikely to win a vote in the House of Commons, leading politicians have told the FT.

Last month, the UK helped to lift an EU embargo that prohibited the shipment of arms to either side in the Syrian civil war.

In repeated interviews since then, Cameron has said that the lifting of the arms embargo does not mean the UK has yet taken a decision to ship arms.

However, Cameron has been forced to concede that he would hold a vote in the Commons ahead of any decision to transfer arms, giving all MPs the right to decide for themselves whether arms should be transferred.

Senior Conservatives say there is little support for such a move within the party, where many MPS believe it would reawaken fears about the way the UK got embroiled in the deeply unpopular Iraq and Afghan wars.

“There is a fear that Cameron would get dragged into another Afghanistan situation where the UK is engaged without any end in sight,” said one Tory MP. “There is also a sense that we cannot waste finite resources on possibly un-winnable wars.”

Politicians also have mixed feelings about the outcome of the 2011 Libyan conflict, which saw the toppling of Muammer Gaddafi and has often been described as a foreign policy success for Cameron.