Britain has expelled five Libyan diplomats to protest at the Libyan government's actions and because they could pose a threat to national security, foreign secretary William Hague said today.
"To underline our grave concern at the regime's behaviour, ... we have today taken steps to expel five diplomats at the Libyan embassy in London, including the military attache," Mr Hague told parliament.
"The government also judged that, were those individuals to remain in Britain, they could pose a threat to our security."
The diplomats have been given seven days to leave, a government source said.
The diplomats were among the strongest supporters of Libyan leader Colonel Muammar Gadafy at the embassy, a spokeswoman for prime minister David Cameron said.
She said they had been putting pressure on Libyan students and the Libyan opposition in Britain.
Britain hosted an international conference on Tuesday that piled pressure on Col Gadafy to quit and pledged to continue military action against his forces until he complies with a UN resolution to protect civilians.
Britain long treated Libya as a rogue state. The 1984 shooting of a London policewoman from inside the Libyan embassy, the Libyan arming of IRA guerrillas in Northern Ireland and the 1988 Lockerbie airline bombing over Scotland, for which a Libyan was convicted, contributed to Col Gadafy being branded a pariah.
After Col Gadafy agreed in 2003 to abandon efforts to acquire chemical, biological and nuclear weapons, then prime minister Tony Blair helped lead him back into the international fold, opening the way for lucrative business deals.
But since protests against Col Gadafy's rule began, Britain and France have led the no-fly zone over Libya.
At the London meeting, the question of arming Libyan rebels moved up the international agenda, although both Britain and the United States said they had taken no decision to supply arms.
Today, Mr Cameron repeated that line, but said Britain did not rule out supplying weapons to the rebels.
Mr Hague announced that a British diplomatic mission, headed by senior diplomat Christopher Prentice, had visited the rebel-held city of Benghazi yesterday and today and met key opposition groups, including Mustafa Abdel Jalil, head of the rebel Libyan National Council.
The opposition Labour Party's foreign affairs spokesman Douglas Alexander, citing a comment by Nato's top operations commander today that intelligence on the rebels had shown "flickers" of al-Qaeda or Hezbollah presence, said the case for supplying arms to the rebels had not been made.
Mr Hague said introducing new weapons into a conflict could have "unforeseeable and unknown consequences". "Such considerations would have to be very carefully weighed before the government changed its policy on this matter," he said.