The Foreign Secretary today insisted five months of military action against Libya had been a success - despite leader Colonel Muammar Gaddafi remaining in power.
William Hague insisted the United Nations-backed air strikes saved "many thousands of lives and stopped the destabilisation of Egypt and Tunisia".
He said: "What we have done so far has been a success in achieving the objectives of saving civilian life.
"Now we want to see a political settlement and that involves the departure of Col Gaddafi."
But Mr Hague appeared to leave the door open for Col Gaddafi to remain in Libya if he stands aside as leader - despite the International Criminal Court previously issuing a warrant for his arrest.
"It's up to the people of Libya what happens in the end. We are not going to stand in their way of an eventual solution," said the Foreign Secretary.
"But I also said, as did my colleague the French foreign minister, that... the best feature of any solution will be Col Gaddafi leaving Libya as well as leaving power."
The UK Government last week officially recognised the Libyan rebels' National Transitional Council (NTC) as the country's legitimate government, inviting its representatives to move into the Libyan Embassy in London.
The Foreign Secretary said the move was essential for planning Libya's future post-Gaddafi.
And Mr Hague denied splits among the countries backing Nato air strikes in Libya, claiming: "The international community is united.
"No-one should mistake our determination and our unity in carrying this through to success and that involves supporting the NTC."
Speaking to BBC Radio 4's Today programme, he pledged Britain's backing to "follow through" the mission in Libya.
But he admitted: "We don't know how long it will be.
"I have always resisted saying how long. I have never put a forecast on it.
"We don't know when Col Gaddafi will see that he has to go. We don't know when members of his regime will come to that conclusion."
Meanwhile, Defence Secretary Liam Fox predicted Col Gaddafi would be toppled by his "close circle" deserting him.
Dr Fox admitted the Libyan rebels had "limited capacity" to win a lengthy ground war.
Speaking to The World This Weekend before flying to meet his opposite number in Washington, Leon Panetta, to discuss defence cuts and Libya, Dr Fox conceded the rebels had "always had limited capacity on the ground".
He said: "They are being assisted in terms of communications and their logistics and making the best use of the equipment that they have.
"They may be getting equipment from elsewhere but they will still have limited ground potential."
But he said Col Gaddafi would be defeated when he was abandoned.
"The key to the Libyan resolution will be whether or not the close circle around Col Gaddafi recognise there is no point investing in him, he is a busted flush, and that he will sooner or later have to leave power," said Dr Fox.
Downing Street denied any conflict between the ICC warrant and leaving open the option for Gaddafi not to be forced out of Libya.
"The ICC's position still stands and we support that. But we also, as another country, have to recognise the fact that the Libyan people should determine their future," a spokeswoman said.
She also said the UK would await the results of an investigation before drawing conclusions about the killing of Abdel Fattah Younes, a former government minister who defected to the rebels.
The death of the chief military commander on Friday appeared to have caused disarray in rebel ranks amid reports he was killed by comrades after being arrested on suspicion of treason.
The Gaddafi regime claimed the death proved that Britain had made a mistake in recognising the rebel National Transitional Council as the "sole governmental authority".
"The position remains unclear, what actually happened. We are not going to draw any conclusions before investigation is completed but it doesn't detract from the central aim of the NTC and that is to protect civilians," Downing Street said.
Dr Fox was speaking "on the behalf of the Government" in his remarks about the possible fate of Gaddafi but his remarks did not represent any shift in the official position, the spokeswoman said.
Nato said its latest air strikes had successfully targeted state TV satellite transmitters in a bid to silence the regime.