Nato attacks on Monday and Tuesday, unusually taking place in daylight hours, were the first on the city centre for two weeks and a sign that commanders are keen to prevent a stalemate forming.
William Hague, the foreign secretary, admitted at the weekend that the campaign could last beyond Christmas, but at the same time ministers acknowledge that the situation is unpredictable.
They have also ordered officials to speed up preparations for a post-Gaddafi transition so that they are ready in two weeks.
Whether the raids will succeed in scaring Col Gaddafi out of hiding, or even killing him, is another matter. A senior Libyan official told The Daily Telegraph that the bunker built by the "Brother Leader" under Tripoli as a last redoubt was reinforced to withstand a nuclear attack.
"Do you think he will not be keeping safe?" the official said. "His bunker is reinforced against nuclear attack. Nato air strikes cannot damage it."
The attacks may be aimed at encouraging more defections. Five generals and the oil minister, Shukri Ghanem, fled Libya last week alone, to be joined today by the labour minister, Al-Amin Manfur.