The flow of foreign recruits has increased significantly in the past two or three months

Syria is now the world’s foremost terrorist training ground, with as many as 10,000 foreigners fighting to overthrow President Assad, US intelligence sources say. Up to 150 Britons are among the European contingent. “A few hundred, mostly Sunni, Europeans, have travelled to reach the fight,” a US official said.

The flow of foreign recruits has increased significantly in the past two or three months, according to diplomatic sources, analysts and members of the Syrian opposition. They say the rise coincides with the surge of Shia militants from Iraq and Lebanon who have entered Syria to fight on behalf of the Assad regime.

Syria has replaced Afghanistan, Pakistan and Somalia as the favoured training ground for jihadists and terrorists, counter-terrorism experts acknowledged. The presence of so