The Libyan ambassador to the UK has reportedly left the country after being expelled by the Government following attacks on the British embassy in Tripoli.
Foreign Office officials said Omar Jelban left the UK on Monday evening after William Hague ordered him to leave the country within 24 hours on Sunday.
The Foreign Secretary said Mr Jelban was "persona non grata" and accused the Libyan authorities of failing to protect foreign diplomatic missions.
Rooms inside the empty British embassy were reportedly set alight and ransacked by a mob on Sunday.
Embassies belonging to a number of Nato states including America, France and Italy were also targeted by mobs in Libya's capital over the weekend after an air strike reportedly killed Muammar Gaddafi's youngest son Saif al-Arab and three of his grandchildren.
Mr Hague said: "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."
Mr Hague expelled the Libyan ambassador, who met the Queen at Buckingham Palace in 2010, stating he was a "persona non grata pursuant to Article 9 of the Vienna Convention on Diplomatic Relations".
Meanwhile, further fighting took place on Monday in the besieged coastal city of Misrata - the last remaining rebel-held city in western Libya.
The rebel interim National Council's senior spokesman Abdel Hafiz Ghoga urged Nato to step up air strikes on Gaddafi forces near the city, saying they are trying to destroy the port.
Mr Hague said Nato would intensify military operations in Libya, adding: "Time is not on the side of the Gaddafi regime. The policy is to continue to increase pressure on the Gaddafi regime - diplomatic, economic and military pressure. We have increased the pace of the military operations under UN resolution 1973 and will go on doing so."