Prime Minister Gordon Brown has said there was "no conspiracy" leading to the release of the Lockerbie bomber.
He added there had also been "no cover-up" over the UK's dealings with the Scottish or Libyan governments.
Speaking in Birmingham, Mr Brown did not refer to the fact Libyan officials were told he did not want to see the bomber, who has cancer, die in jail.
Libyan Abdelbaset Ali al-Megrahi was released last month by the Scottish government on compassionate grounds.
The BBC understands Megrahi has had chemotherapy and is now in a cancer ward at a hospital in Tripoli.
The Scottish government has been defeated by 73 votes to 50 after a Holyrood debate about its decision to release Megrahi.
And in a further development, a lawyer who represents the families of Lockerbie victims in the US is planning legal action to force the US government to publish details of its correspondence with London and Edinburgh in the run-up to Megrahi's release.
Megrahi was freed earlier this month, eight years into a life sentence imposed for his part in the bombing of Pan Am flight 103 over Lockerbie in December 1988, killing 270 people.
The Scottish government, which deals with criminal justice matters in Scotland, said the decision had been made on compassionate grounds, as Megrahi has terminal cancer.
But the release was opposed by the US government and Megrahi's return to Libya, amid triumphant scenes, caused widespread anger in the UK and US.
On Tuesday, Scottish officials released a report saying a Libyan official had said Foreign Office minister Bill Rammell had told them Mr Brown did not want the Lockerbie bomber to die in a Scottish prison.
Mr Rammell - and UK foreign secretary David Miliband - have since confirmed that this report was accurate.
Mr Brown did not directly refer to the suggestion the Libyans had been told he did not want to see Megrahi die in a UK prison.
But he said: "I respect the right of Scottish ministers to make the decision, and the decision.
"But on our part here was no conspiracy, no cover-up, no double dealing, no deal on oil, no attempt to instruct Scottish ministers, no private assurances by me to [Libyan leader] Colonel Gaddafi."
He said the release of Megrahi was a matter for the Scottish government.
Mr Brown also said: "Our interest throughout has been to strengthen the coalition against international terrorism. I made it clear that for us there was never a linkage between any other issue and the Scottish government's own decision about Megrahi's future."
The SNP's Angus Robertson said Mr Brown had "finally confirmed that he is in support of the decision and the way in which it was made".
But Conservative leader David Cameron said Mr Brown's comments were unsatisfactory.
He repeated his call for an inquiry to look into all discussions between UK and Libya about the Megrahi case, including Tony Blair's meeting with Libyan leader Colonel Gaddafi in 2007 and Bill Rammell's visit to Libya in February.
"We cannot now trust the government to give us the information about what happened in this sorry saga," he said.
It does not feel right to me that someone who has been convicted for an extremely serious offence be able to return...to Libya
Jacqui Smith, Former Home Secretary
The Liberal Democrats said Mr Brown had "felt able to share his feelings with a power-crazed dictator but not with the British people" and called for all minutes of meetings between Libyan and British ministers to be released.
Scottish Justice Secretary Kenny MacAskill allowed Megrahi to be freed from Greenock Prison on 20 August on compassionate grounds after rejecting his return to Libya under a prisoner transfer agreement.
Mr Brown and other UK ministers have declined to say whether they supported freeing Megrahi, stressing it was a decision for the Scottish government.
During Wednesday's debate in the Scottish Parliament, Scottish ministers were accused of mishandling the decision and making a mistake of "international proportions" by opposition parties.
But Scottish First Minister Alex Salmond said the details of the discussions between Libyan and British ministers about Megrahi's fate had left Labour looking "absolutely ridiculous".
Former home secretary Jacqui Smith has become the most senior Labour politician to criticise the decision to release Megrahi, saying it did not "feel right".
While stressing she had not seen all the information in the case, she told the Jeremy Vine Show on BBC Radio 2 that she thought Megrahi's return to Libya was "bad".
"It does not feel right to me that someone who has been convicted for an extremely serious offence be able to return, in a way in which his victims were not able to, back to Libya.
"Of course we have to be compassionate with people who are in prison and coming to the end of their lives but I am not sure I would have made the same decision."
But Ms Smith defended Gordon Brown's explanation of the government's position saying he had been "very clear" that it was a matter for the Scottish administration and that there had been no double-dealing or conspiracy.
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