Prime Minister David Cameron today promised that Britain will "stick to our task" in Libya, as he revealed that RAF pilots have already notched up more than 120 sorties and 250 flying hours as part of international military action to protect civilians.
Mr Cameron paid tribute to the "extremely skilful and dangerous" work of airmen who have targeted dictator Muammar Gaddafi's forces while "doing everything possible to avoid civilian casualties".
Tornado GR4 jets from RAF Marham in Norfolk flew deep into the Libyan desert in the early hours of this morning to destroy ammunition bunkers at Sabha being used by Gaddafi's military to attack opposition-held towns like Misrata.
And 22 of Gaddafi's tanks, armoured vehicles and big guns were hit by RAF Tornados flying sorties near Misrata and Ajdabiya over the weekend, the Ministry of Defence said.
Gaddafi's troops have now been driven from Ajdabiya and rebels were today celebrating the seizure of the key oil towns of Brega and Ras Lanuf and are nearing the dictator's hometown of Sirte, a key regime stronghold.
But Mr Cameron said the situation of civilians in Misrata and Zintan remains "extremely grave", with both under heavy attack.
He told MPs that allied operations have had a "significant and hugely beneficial effect", stopping Gaddafi's assault on Benghazi, the cradle of the uprising, and creating the conditions for the liberation of towns like Ajdabiya, Ras Lanuf and Bin Jawad.
"The no-fly zone is now fully operational and effective," said Mr Cameron in a statement to the Commons. "When it has been challenged, Gaddafi's planes have been shot down. He can not terrorise the Libyan people from the air."
He added: "We have moved quickly and decisively over the last week and we will stick to our task, as set out in the UN Resolution, and take all necessary measures to protect civilian life."
Mr Cameron and French president Nicolas Sarkozy released a joint statement setting out the objectives of an international conference on Libya being hosted by the UK in London tomorrow.
They pledged that military operations would end "only when the civilian population are safe and secure from the threat of attack".
The current regime has "completely lost its legitimacy" and Gaddafi must "go immediately", the statement by Mr Cameron and Mr Sarkozy said, calling on the dictator's supporters to "leave him before it is too late".
They stressed that they do not envisage any military occupation of Libya, and said that the north African state's political future must be determined by the Libyan people themselves.
Tomorrow's conference will bring together around 40 delegations, of all members of the coalition involved in the military operation, as well as the United Nations, Nato, the African Union and the Arab League. Arab countries Qatar, Iraq, Jordan, Morocco, Lebanon, Tunisia and the United Arab Emirates will be there.
The conference will "bring the international community together to support Libya's transition from violent dictatorship and to help create the conditions where the people of Libya can choose their own future", said Mr Cameron and Mr Sarkozy's statement.
It added: "We call on all Libyans who believe that Gaddafi is leading Libya into a disaster to take the initiative now to organise a transition process.
"In our view, this could include the Interim National Transitional Council, the pioneering role of which we recognise, the civil society leaders as well as all those prepared to join the process of transition to democracy. We encourage them to begin a national political dialogue, leading to a representative process of transition, constitutional reform and preparation for free and fair elections."
Downing Street said the UK was in diplomatic contact with the transitional council. It is unlikely the Libyan opposition would be formally represented at tomorrow's conference but it is understood the UK will ensure participants are made aware of its views.
Russia, which has said the attacks on Gaddafi's forces on the ground went beyond the terms of the United Nations Security Council resolution which authorised a no-fly zone, will not be taking part. France will be represented by foreign minister Alain Juppe and the US by Secretary of State Hillary Clinton.
The Prime Minister told MPs that the conference would help maintain pressure on Gaddafi's regime by ensuring "maximum political and diplomatic unity around the world".
The aims of the conference will be to strengthen the alliance with more support from new countries, including in the Arab world; to ensure the delivery of humanitarian aid; and to help plan for the future of Libya after the conflict is over.
"In the last few weeks, the Libyan people have demonstrated their courage and their determination. Like all other peoples, they have the right freely to choose their leaders," said Mr Cameron and Mr Sarkozy's statement.
"We must unite to help them make a new beginning."
As Nato took over command and control of military operations in Libya today, its Secretary General Anders Fogh Rasmussen said action would be taken to protect civilians if they are threatened by rebel forces, as well as those of the Gaddafi regime.
"Our obligation is to ensure full implementation of the UN Security Council resolution and protect civilians against all attacks," Mr Rasmussen told the BBC.
"I don't think the rebels will attack civilians. If so, we have to protect civilians against attack.
"Those who attack civilians will also be our targets but I have to stress that until now it is the Gaddafi regime that has attacked its own people."
Mr Rasmussen declined to disclose the exact terms of Nato's rules of engagement in Libya or to estimate how long the current operations may take.
"It is premature to lay out any timetable but I hope to see a peaceful resolution to the problems in Libya as soon as possible," he said.