Britain has ordered the expulsion of the Libyan ambassador to London, Omar Jelban, in retaliation for an attack on the British embassy by a pro-Gaddafi crowd in Tripoli.
Jelban has been given 24 hours to leave the country.
"I condemn the attacks on the British embassy premises in Tripoli as well as the diplomatic missions of other countries," said the foreign secretary, William Hague. "The Vienna convention requires the Gaddafi regime to protect diplomatic missions in Tripoli. By failing to do so that regime has once again breached its international responsibilities and obligations. I take the failure to protect such premises very seriously indeed."
The statement went on: "As a result, I have taken the decision to expel the Libyan ambassador. He is persona non grata pursuant to article 9 of the Vienna convention on diplomatic relations and has 24 hours to leave the country."
According to Foreign Office sources, the building housing both the British embassy residence and its chancellery was burned down by a mob early on Sunday. The attacks on the British and other western embassies followed the Nato missile strike on one of Muammar Gaddafi's villas, which the Libyan government says killed his youngest son, Saif al-Arab.
The Gaddafi regime appears to have mounted a symbolic attack on empty diplomatic residences and embassies in Tripoli. There are no British diplomats in the Libyan capital.
Other foreign residences were also targeted, as the UN announced it was taking all its remaining international staff out of Tripoli.
The Italian foreign ministry said its embassy and several others in Tripoli were damaged by vandals and accused the Gaddafi regime of failing to take measures to protect foreign missions.
The ministry issued a statement on Sunday following reports from Tripoli that a fire had broken out at the Italian embassy.
A witness told Reuters news agency: "I am across the road from the Italian embassy. I can see smoke still coming out of the embassy. It was on fire. There is no one there now, just a security car to stop other people coming."
Some reports suggest that the buildings were attacked by mobs.
Foreign correspondents in Tripoli have been unable to visit the sites to confirm the reports.
Most of the diplomats pulled out of Tripoli when the Nato no-fly zone was imposed. The UK is maintaining a diplomatic presence in Benghazi, the rebel-held city in the east of the country.
