His comments came after the airlift of 150 oil workers, many of them British, from desert camps in Libya. About 300 British nationals remain stranded.
Speaking on the BBC Andrew Marr programme, Mr Hague said: "Of course, it is time for Colonel Gaddafi to go, that is the best hope for Libya."
The UK has withdrawn his diplomatic immunity on British soil, he added.
The order also applies to his family and household.
"It is very clear where we stand on his status as the head of state," he said.
Mr Hague also confirmed that former prime minister Tony Blair had kept the government informed about telephone conversations he had had with the Libyan leader over recent days.
The foreign secretary said the UK was "working intensively" to establish how many Britons remained in Libya and said the Foreign Office "continued to urge British nationals to leave" the country.
Rescue flights
The Foreign Office has issued advice and information on possible options for leaving:
* The Royal Navy frigate HMS Cumberland has arrived in Benghazi and is now expected to depart at dusk on Sunday. Those on board will be met in Malta and flown to the UK on Monday or Tuesday
* One flight carrying rescued oil workers left Malta for Gatwick at 1500 (local time) on Sunday carrying 148 passengers, 79 of whom were British. A second FCO-chartered plane will leave the island either later on Sunday, or on Monday
* The Hungarian government has organised a charter flight out of Tripoli on Sunday and is willing to accept British nationals
* The Romanian government is also sending a plane to Tripoli on Sunday, with availability for approximately 40 EU citizens. It is expected to arrive at 1400 and leave at 1900 (Libyan time)
* Where it is safe to do so, UK citizens can consider leaving Libya by road via the Tunisian border, which is open
* Further rescue missions are planned to reach the British nationals still stranded
* More details are on the Foreign Office website and all options to depart Libya will also be updated on the Foreign Office on Twitter.
The Foreign Office has revised upwards its original estimate of the number of British oil workers still in the desert.
It now estimates there could be between 280 and 380 British nationals still in the country - and is urging those who have already left to contact them on 0207 008 0000 to ensure they have been accounted for.
However it is believed some Britons want to remain in Libya - in some cases because they have dual nationalities or have Libyan spouses or families.
Evacuation effort
On Saturday, 53 Britons and consular staff were among 100 on the last government-chartered flight out of Libya to Gatwick.
The Foreign Office has closed the British embassy in Tripoli, leaving a skeleton staff working in a different building.
But former UK ambassador to Libya and deputy chairman of the Libyan British Business Council, Oliver Miles, said he believed that decision was "shocking" and wrong.
"Why have we closed the embassy, when as William Hague said, we've got humanitarian aid measures ready on either border?
"We've got still British subjects in trouble inside Libya and we've got presumably the prospect, we hope, of some kind of new government which will immediately need to get in touch with the rest of the world and will need help," he said.
Also on Saturday, two RAF Hercules flew the 150 oil workers to the safety of Malta.
Mr Hague said Libyan authorities had not given permission for the rescue operation - despite being contacted - but the UK government felt "it was the only sure way to get people out of the desert".
The BBC's Europe editor Gavin Hewitt, who is in Malta, says the RAF flights on Saturday were into an area which was "relatively safe" because the landing strip had been secured by local militia, and by oil company security.
He says "there are much more complicated and difficult places where there are still British workers", and rescue plans for them are being worked out.
"The biggest fear is of landing in an area that is not in under the control of one side or the other," he added.
Defence Secretary Liam Fox confirmed the Hercules flights on Saturday evening, once they had arrived in Malta, and gave detail of other evacuation efforts.
"HMS York has arrived in Valletta to take on board stores so it can assist the evacuation effort if required. And a number of other military assets remain available to support the FCO-led efforts to return civilians from Libya," he said.
The Foreign Office said the Hercules passengers had been met by a team of consular officials and Red Cross staff in Valletta, where they would be helped before returning to Britain on a government-chartered plane on Sunday or Monday.
Shadow defence secretary Jim Murphy commended the "remarkable bravery" shown by British forces and said it provided the government "with an opportunity to move on from the incompetence and complacency of last week".
Meanwhile Deputy Prime Minister Nick Clegg told Sky News that the rescue had been "meticulously planned and extremely well executed".
"We have been very open about the fact, the Prime Minister has sort of apologised for the fact, that the initial reaction, because of the delay in the deployment of a charter plane, was clearly not as quick as we wanted and there were many people in Tripoli airport and elsewhere who were having to face immense uncertainty and huge anxiety," he added.
Much of Libya, especially the east, is now controlled by anti-Gaddafi forces but the Libyan leader, who is coming under increasing pressure from the international community over his crackdown against protesters, still controls Tripoli.
The capital is home to two million of the country's 6.5 million population.
source : bbc.co.uk
source : bbc.co.uk
