Defiance chiefs told the prime minister that sending small arms or ground to air missiles is ‘hardly worth it’ since it would make little difference to the outcome of the conflict.

General Sir David Richards, Chief of the Defense Staff, and other commanders told Cameron that even options like a no-fly zone would require air attacks on Syrian defenses lasting weeks or even months.

Instead, senior ministers and Whitehall officials have revealed that Britain is drawing up plans to help train and advise more militant forces battling Al Assad’s government.

Cameron has been keen to act on Syria and demanded an end to the EU arms embargo on the country at the end of May to give him options. But he has been warned that he has little prospect of winning a vote in the Commons if he sought to send weapons.

The military were asked to present options at a meeting of the National Security Council last month on the conflict.

“There are three things you (Cameron) can do: arm, train and advise. What you’ll see from us are the elements where we can bring something to the game and that means training and advising. It is not possible to send enough military kit to put the rebels on a level playing field with the regime. What they lack is organization,” defense chiefs said.

Cabinet members also backed the military and said there was ‘little point’ in Britain contributing arms since states such as Qatar and Saudi Arabia are already sending weapons.

“We need to concentrate on areas where we have expertise.”

It is understood that military advisers could be stationed in Jordan to advise Syrian militant groups’ leaders on strategy and tactics.

UK chiefs are wary of being accused of having British boots on the ground in Syria. Ministers believe it could take 18 months of further conflict before Al Assad government is forced to the negotiating table.

NJF/NJF