UK special forces have been operating in Libya since January, according to a leaked memo from a confidential briefing delivered to US lawmakers by the king of Jordan.

King Abdullah met congressional leaders in January, briefing them on a range of strategic matters relating to the fight against Isis in Libya, the civil war in Syria and the threat posed by al-Shabaab militants in Somalia.

Leaked notes from the meeting state that Jordan’s own special forces “will be imbedded [sic] with British SAS” in Libya.

Suspicions that the UK had deployed SAS troops to Libya, which descended into political chaos after the fall of Colonel Gaddafi in 2011 following a Western intervention spearheaded by Britain and France, have been rife for several weeks.

Responding to reports of the leak, the Ministry of Defence said it did not comment on special forces’ operations. However, intelligence analysts Stratfor said earlier this month that British and US forces were operating in western Libya, while French special forces had established themselves in the east around Benghazi, with the goal of combatting Isis, which has capitalised on the political chaos to gain a foothold in the country.

Earlier this week, David Cameron was challenged by the Scottish National Party’s Westminster leader Angus Robertson to confirm or deny the presence of special forces, after he said in a carefully worded statement that Parliament would be consulted if there were plans to send “conventional forces” to train Libyan forces.

Mr Cameron said the Government had a “longstanding policy” of not commenting on special forces. He told MPs: “The work that our special forces do is vital for our country. Like everyone in this country, they are subject to international law, but I do not propose to change the arrangements under which these incredibly brave men work.”