Scottish prosecutors today told the Foreign Office they want to interview Musa Kusa in connection with the Lockerbie bombing.
The Crown Office said prosecuting and investigating authorities want to speak to the former Libyan foreign minister over the 1988 bombing of Pan Am 103 over Lockerbie.
A spokesman said: "We have notified the Foreign and Commonwealth Office that the Scottish prosecuting and investigating authorities wish to interview Mr Kusa in connection with the Lockerbie bombing.
"The investigation into the Lockerbie bombing remains open and we will pursue all relevant lines of inquiry."
Libyan foreign minister Musa Kusa fled to the UK after deciding he was "no longer willing" to represent the dictator on the world stage.
Mr Kusa arrived at Farnborough Airport in Hampshire from Tunisia last night.
A key player in Colonel Muammar Gaddafi's regime, he previously acted as the country's representative in Britain.
He became Libya's foreign affairs minister in March 2009 having headed the Libyan intelligence agency from 1994 to 2009.
He was widely credited with persuading the dictator to reach an accommodation with the West and stop developing weapons and funding terrorism.
He is believed to have played a key role in securing the release of the only man convicted of the Lockerbie atrocity, Abdelbaset Ali Mohmed al-Megrahi - and is thought to hold vital information about the bombing.
The inquiry into the bombing of Pan Am Flight 103 has remained open.
The Boeing 747 jumbo jet was en route from London to New York when it was blown out of the sky over the Dumfriesshire town. Some 243 passengers, 16 crew and 11 residents of the town were killed and debris from the aircraft was spread over 845 square miles between Lockerbie and the North Sea.
Megrahi was convicted at Camp Zeist in the Netherlands in 2001 but released from jail in August 2009 on compassionate grounds after the Scottish Government was told he had only three months to live.
Calls for Mr Kusa to be questioned over the bombing have been made throughout the day.
Conservative MP Robert Halfon, who has tabled several parliamentary motions on Lockerbie, said Mr Kusa "should be put in front of a British or international court for war crimes, if it is true that he was behind the Lockerbie bombing".
He added: "Anyone who was involved in any kind of crime in Libya - including Gaddafi himself - should not be allowed to go into exile but should be put on trial in an international court for war crimes."
Jim Swire, whose daughter Flora was killed in the bombing, said he thought Mr Kusa "knows everything".
He said: "He was clearly running things. If Libya was involved in Lockerbie, he can tell us how they carried out the atrocity and why."
Conservative MP Patrick Mercer told the BBC News Channel that the authorities' first priority must be to question Mr Kusa "very carefully" for the wealth of military and diplomatic intelligence he possesses, as well as his understanding of the "heartbeat of the Gaddafi regime".
But he added: "What advantage he gives to us and to the rebels must be balanced by what he has done in the past.
"The fact remains that if this man has carried out crimes or been involved in criminal activity, then he must be brought to justice."
A Downing Street spokesman said the investigation into Lockerbie remained a matter for authorities in Scotland.
He said any decisions under the International Criminal Court process set up by UN Security Council Resolution 1970 were for the overseeing prosecutor.
Dumfries and Galloway Police said they remained "determined to pursue all relevant lines of inquiry".
Detective Superintendent Mickey Dalgliesh said: "Dumfries and Galloway Constabulary are aware that Crown Office have been in contact with the Foreign and Commonwealth Office advising them that Scottish prosecuting and investigating authorities wish to interview Mr Kusa in connection with the Lockerbie bombing.
"This is in line with our position that the investigation into the Lockerbie bombing remains open and we are determined to pursue all relevant lines of inquiry."
Earlier today, Foreign Secretary William Hague said Mr Kusa "is not being offered any immunity from British or international justice".
He said he is "voluntarily talking" to British officials.
A Foreign Office spokesman said: "We can confirm that we have been informed by the Crown Office Serious and Organised Crime Division that they wish to speak to Mr Musa Kusa in relation to information that he may have regarding the Lockerbie bombing.
"As the Prime Minister has made clear we will respond to any request. The police are independent and should follow evidence wherever it takes them."