By Ross Hawkins
Political correspondent, BBC News
The view of Gordon Brown's government on the release of the Lockerbie bomber has been straightforward if unrevealing.
Mr Brown is coming under pressure from political rivals to speak
It was, spokesmen have repeatedly said, a decision for Scottish Justice Secretary Kenny MacAskill.
That is why the prime minister will not say whether it was right or wrong to allow Abdelbaset Ali al-Megrahi to return to Libya, where he received a jubilant greeting.
But the political realities are much more complicated.
Justice is a matter for the Scottish government. Foreign affairs are not.
And the furious response to the release from FBI director Robert Mueller and others in the US made it clear the Scottish decision had become an international row.
Libyan leader Colonel Gaddafi did not make the prime minister's life any simpler when he publicly thanked "my friend Brown" and the Queen, as well as the Scottish authorities, for Megrahi's return.
His son, Saif al-Islam, added to the complications when he said the prisoner's release was "always on the negotiating table" during talks about commercial contracts for oil and gas.
Business Secretary Lord Mandelson said the idea the British and Libyan governments would barter over the freedom of a prisoner as part of a business deal was wrong, implausible and offensive.
It is clear Megrahi's fate did come up in negotiations between Britain and Libya. Lord Mandelson - who has met Saif al-Islam twice this year - and former Prime Minister Tony Blair have both explained that the Libyans raised the issue repeatedly.
Both Lord Mandelson and Mr Blair said their response had always been the same. They told the Libyans it was a decision for the Scottish government.
The arguments and allegations are unsurprising. As Britain's relations with Libya have improved, ministers at Westminster have repeatedly assured their Scottish counterparts that no deal was struck on Megrahi's fate, and that the decision about his future would rest with Scotland.
They can argue they have been consistent. And they can insist Mr Brown is not about to break his current holiday to comment.
None of that convinces their political opponents.
Liberal Democrat leader Nick Clegg has called the prime minister's silence "absurd and damaging".
Conservative leader David Cameron wasted no time airing his opposition to Megrahi's return, and demanding an opinion from Number 10.
If the prime minister said the release was wrong, he could damage relations with Libya. Were he to say it was right, he would further inflame passions in the US.
And four days after Megrahi took off from Glasgow airport, if Mr Brown did change his mind and make public his opinion on the release now, he would be accused of performing a U-turn.
None of that will stop him being asked whether Mr MacAskill did the right thing when he let the prisoner go home.