The Foreign Office was facing embarrassment tonight as its first rescue flight for British nationals stranded in Libya was stuck on the tarmac at Gatwick with a mechanical fault.
With hundreds of Britons waiting to be flown out of Tripoli airport, the Boeing 757 had still not left after 5pm. It had been due to leave at 12.30pm.
The delay came after British nationals and shadow foreign secretary Douglas Alexander accused the Foreign Office of taking too long to respond to the chaos that has engulfed Libya.
Foreign Secretary William Hague promised to send as many rescue flights to Libya as were needed to evacuate Britons wanting to leave.
Two were due to leave today and a third - if necessary - early tomorrow morning.
At least 300 Britons are in and around the Libyan capital Tripoli, while up to 170 more - mainly oil workers - are in remote desert camps at risk of attack as violence continues.
Mr Hague said that, as well as laying charter planes, he was not ruling out the possibility of using military flights "without permission".
Royal Navy frigate HMS Cumberland is on its way to the Libyan coast to evacuate Britons around the Benghazi area.
But in a statement this afternoon, Mr Hague insisted: "We are taking every action to get the remaining British nationals in Libya out of harm's way."
The first of the Foreign Office flights - free for British nationals, unlike similar flights to and from Egypt recently - was hoped to return to the UK later today.
However, the 200-capacity Boeing 757 still was still at Gatwick at 5pm despite previously being billed to depart for Tripoli at 12.30pm.
Foreign Office minister Alistair Burt said the plane, which was meant to arrive by 9.30pm, was being fixed.
"Sometimes planes develop faults through nobody else's fault or error," he told the BBC. "We will hopefully get those planes out as quickly as possible."
