Two British military aircraft swooped into strife-torn Libya on Saturday and evacuated more than 150 foreign nationals from remote camps in the desert, the defence minister said.
The Royal Air Force C130 Hercules transport planes involved in the daring rescue later landed in Malta after picking up the civilians from south of Benghazi, said Defence Secretary Liam Fox.
Britain also closed its embassy in Tripoli after evacuating all staff on the last government-chartered flight out of the the capital, amid mounting violence by forces loyal to Libyan leader Moamer Kadhafi.
"I can confirm that two RAF C130 Hercules aircraft have evacuated more than 150 civilians from desert locations south of Benghazi," Fox said.
The mission was cloaked in secrecy but Sky News reported that it involved troops from Britain's elite Special Boat Service who are normally tasked with maritime counterterrorism.
It said the planes entered Libyan airspace without permission and flew to the town of Nafoora in eastern Libya, before splitting up and heading to Amal and Wafa in the oil fields.
British newspapers reported that the workers were scattered in different compounds and that it was difficult to get the message to all Britons.
"While we sat on the aircraft waiting to take off there were reports of gunfire and all of a sudden another 20 or 30 guys were stuffed on the aircraft and we took off," Nigel Bilton, one of those rescued, was quoted as saying by The Sunday Times.
"I think things were starting to hot up. We flew treetop all the way across the desert, it was quite spectacular. It was a big, big relief to see those guys," said Bilton, who was working for Siemens in southern Libya.
The defence ministry said it would not comment on the movements of special forces and gave no further details.
Those on the rescue flights would be given food and water and a medical before being taken to hotels, the government said. They would return to Britain on a charter flight on Sunday or Monday.
Separately the British frigate HMS Cumberland is returning to Benghazi on Sunday to evacuate any other British nationals after bringing evacuees to Malta earlier Saturday.
"A number of other military assets remain available to support the FCO (Foreign and Commonwealth Office)-led efforts to return civilians from Libya," Fox said.
There are at least 250 British nationals left in Libya, most of them still in desert camps, the Foreign Office said, although it added that a number were leaving "under their own steam".
Britain's government has faced criticism at home for being too slow to help hundreds of oil workers stuck at desert camps, who complained they faced the threat of looters as well as diminishing supplies of food and water.
Britain meanwhile joined countries including the United States, Australia, Canada and France in temporarily shuttering its embassy in Tripoli.
All embassy staff left on the last flight chartered by the ministry out of Libya, which was due to arrive at London Gatwick airport late Saturday, the Foreign Office said.
"In light of the deteriorating situation in Libya, and as our last FCO charter flight has now left Tripoli, we have temporarily suspended the operations of the British Embassy in Tripoli," it said in a statement.
Turkey would temporarily represent Britain's interests in Libya, although the British proconsul would remain in Tripoli, it said.
The Boeing 737 charter flight is carrying around 100 passengers, 53 of whom are British nationals, including embassy staff and members of a rapid deployment team sent earlier in the week from London.
The HMS Cumberland had arrived at Valletta, Malta, early Saturday with 207 evacuees from 20 countries after a 35-hour Mediterranean crossing through rough seas.
Another British military vessel, the HMS York, was dispatched to Libya from Gibraltar on Friday to help evacuation efforts. The ship stopped in Malta to pick up supplies on Saturday.