Former MP and veteran campaigner Tam Dalyell says the high-level Libyan defector who arrived in the UK this week told him the Gaddafi regime had not been responsible for the Lockerbie bomb and pointed the finger at Palestinian terrorists.
Mr Dalyell also claimed that Scottish authorities could not be trusted to question former Libyan foreign minister Moussa Koussa, who has been a key figure in the Gaddafi regime for most of its 42 years.
The intervention of the former Labour MP for Linlithgow came on another dramatic day in the Libyan crisis, as it emerged the UK government had held discussions with a senior diplomat from the Gaddafi regime and the rebels called for a ceasefire.
With both sides making gains and losses in continued fighting, there were reports that other senior figures in the Gaddafi regime were preparing to follow Mr Koussa, who fled to the UK on Wednesday in a private Swiss jet from Tunisia. He is being kept in a safe house and has been questioned by MI6 officers and diplomats, but the Crown Office in Scotland is still pressing its claim to interview him about Lockerbie.
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Mr Dalyell, who has long campaigned to find the truth behind the murder of 270 people when Pan Am Flight 103 was blown up over Lockerbie on 21 December, 1988, held a one-and-a-half-hour meeting Mr Koussa at an Inter Parliamentary Union conference in Syria in March 2001.
The former MP said: "He asked to see me and we met along with John Cummings, who was then the MP for Easington. He wanted to discuss how to bring Libya back into the international community. Obviously, Lockerbie played a large part in our discussions, but when I asked him about it, he said ‘that was none of my doing'."
Mr Dalyell maintains the real perpetrator of the crime was the Iranian-funded Popular Front for the Liberation of Palestine, headed by Ahmed Jibril, although the main suspect, Abu Nidal, was probably tortured to death by Saddam Hussein's regime in Iraq in 2002.
The organisation has been linked in a conspiracy theory involving a tacit agreement between the US authorities and the Iranian regime to allow a tit-for-tat revenge attack following the shooting down of an Iranian passenger plane in July 1988 by the USS Vincennes, with the loss of 290 lives .
Mr Dalyell told The Scotsman: "When I asked him [Koussa] about Nidal and Jabril, he said ‘you may not be wrong'.
"I do believe he knew a lot more about what happened than he was willing to tell me."
Despite the former spymaster's formidable reputation, Mr Dalyell said he found him "extremely friendly and frank".
"Other people have described him as scary, but I saw none of that," he said.
He also described Mr Koussa as "extremely competent" with "a perfect command of English".
But Mr Dalyell did not believe the Scottish authorities should be allowed to speak to Koussa. He said: "I think that two generations on, the officers at Dumfries and Galloway police force will be under terrible pressure to justify the investigation carried out by their predecessors."
He was more scathing about the Crown Office, which he has criticised for its handling of the case of Abdelbaset Mohmed Ali al-Megrahi, the only man found guilty of the attack, a conviction Mr Dalyell has claimed was wrong. "As I have said before, I believe that at times the Crown Office has been duplicitous about this," he said. "So they would be the wrong people to question him."
He said British diplomat Sir Richard Dalton was best-qualified to lead the questioning of Gaddafi's former close aide.
The Crown Office said it did not wish to comment on an "individual's comments" but that it was still in discussions with the Foreign Office regarding interviewing Mr Koussa over the Lockerbie bombing.
A spokesman said: "We are liaising with the Foreign Office regarding an interview with Mr Koussa. As with any ongoing investigation, we will not go into the details of our inquiries which includes the dates of interviews with any individuals."
Meanwhile, Mohammed Ismail, a senior aide to the Libyan dictator's son Seif al-Islam Gaddafi, has met and had telephone conversations with British officials, who repeated to him their public calls for Gaddafi to quit.
Two people familiar with the matter, who didn't want to be named, said Mr Ismail had been in Britain to visit relatives, and that when officials became aware of this, they took the chance to speak with him.
Both insisted Mr Ismail had not been sent to London on a mission mandated by Gaddafi, nor had been he in the UK in an attempt to open up a new channel of communication between Tripoli and the West.
Mr Ismail has returned to Libya following his visit earlier this week.
The Foreign Office said it would not provide "a running commentary on who we are or are not speaking to" but stressed that in any contacts, "we make it clear that Gaddafi has to go".