BRITAIN has revoked the diplomatic immunity of Libyan leader Muammar Gaddafi and members of his family, Foreign Secretary William Hague says.

He was speaking after the UN Security Council unanimously ordered a travel and assets ban on Gaddafi's regime and a probe into potential crimes against humanity during the attempted crackdown on the revolt against his rule.

Hague also called on Gaddafi to stand down, saying it was the "best hope" for Libya.

"We have here a country descending into civil war, with atrocious scenes of killing of protesters and a government actually making war on its own so of course it is time for Colonel Gaddafi to go. That is the best hope for Libya," he said in a BBC TV interview on Sunday.

"Last night I signed a directive revoking his diplomatic immunity in the United Kingdom but also the diplomatic immunity of his sons, his family, his household.

"So it is very clear where we stand on his status as the head of state."

One of the Libyan leader's sons, Seif al-Islam Gaddafi, has close links to Britain after graduating from the London School of Economics in 2003 and taking a PhD five years later.

Hague also said Britain was "working intensively" to establish how many Britons remained in Libya, amid reports that more than 300 were still in the country, although the Foreign Office declined to confirm that figure.

Dozens of oil workers were dramatically rescued on Saturday when two British military aircraft swooped into remote desert locations in an operation involving special forces.

Hague said the mission was launched without the permission of the Libyan authorities and refused to be drawn on whether further operations were planned.