Libyan officials were secretly told that Gordon Brown wanted the Lockerbie bomber Abdelbaset Ali al-Megrahi to return home rather than have him die on British soil.
The message was conveyed by former Foreign Office minister Bill Rammell after the Libyans had warned that Megrahi's death in a Scottish prison would have a “catastrophic” impact on relations between the two countries.
The revelation was contained in a pile of documents released yesterday by the UK and Scottish governments in an attempt to prove that no deal was struck to return Megrahi in exchange for Libyan oil.
But it increased the pressure on the Prime Minister to end his two-week silence on whether he supported the release of the terminally ill prisoner.
The disclosure was a new setback for Mr Brown who had hoped that the cascade of documents would put an end to the controversy.
David Cameron, the Tory leader, accused Mr Brown of “double dealing” over Megrahi's fate because the US government believed it had a firm promise that the convicted bomber would serve the whole of his life sentence in Scotland.
Megrahi's return last month to Tripoli — where he received a hero's welcome — brought condemnation from around the world. His release came after years of intense negotiations that began with a meeting in 2004 between Tony Blair and Col Muammar Gaddafi, who yesterday celebrated his 40th anniversary of seizing power in Libya.
The documents also disclosed that Jack Straw, the Justice Secretary, warned it would not be “necessary or sensible” to risk damaging relations with Libya by insisting on Megrahi's exclusion from a prisoner transfer deal.
They showed Mr Straw raised the alarm with Edinburgh over the prisoner's failing health nine months before his release.
Reports from Libya yesterday claim Megrahi is now close to death.
And the documents reveal that the Foreign Office denied the US government had been given a binding promise that Megrahi would remain in a Scottish jail for life.
The most damning revelation comes in a note of a meeting between Scottish and Libyan officials six months ago, in which Libya's Minister for Europe, Abdulati al-Obidi, claimed Mr Brown and the Foreign Secretary, David Miliband, backed the prisoner's return home.
According to notes released by the Scottish government, Libya was given the reassurance in Tripoli by Mr Rammell in February. The note said: “Mr Obidi confirmed that he had reiterated to Mr Rammell that the death of Mr Megrahi in a Scottish prison would have catastrophic effects for the relationship between Libya and the UK. Mr Alobidi went on to say that Mr Rammell had stated that neither the Prime Minister nor the Foreign Secretary would want Mr Megrahi to pass away in prison but the decision on transfer lies in the hands of the Scottish ministers.”
There was silence from Downing Street last night, while a brief statement from Mr Rammell, now a Defence minister, failed to deny the Libyan claim.
He only said: “Neither the Libyans or the Scottish Executive were left in any doubt throughout this entire process that this was a decision for the Scottish Executive over which the UK Government sought no influence.
“I made it clear in all my dealings with the Libyans that the decision around Megrahi was exclusively one for the Scottish Executive and the Scottish Executive alone.”
As Mr Salmond insisted the note was accurate, Mr Cameron renewed his call for an independent inquiry into the affair.
He said: “The British Government stands accused — and indeed the Prime Minister stands accused — of double dealing. On the one hand apparently saying to the Americans they wanted Megrahi to die in prison, but on the other hand saying privately to the Libyans that they wanted him released. Now we have got to get to the bottom of this.”
Papers released by the Ministry of Justice showed the Government changed its mind over the question of transferring Megrahi into Libyan custody between July and December 2007.
During these same months BP was waiting for the Libyan government to ratify the biggest oil exploration deal in the company's history, which was drawn up in May of that year and finally sealed in February 2008.
Explaining his change of heart in a letter to Mr Salmond, Mr Straw cited “national interests” and stressed the importance of bringing Libya back into the international community.
Both the UK and Scottish governments stressed yesterday that the tortuous negotiations over the prisoner transfer were academic because Megrahi was not transferred but released on compassionate grounds.