The compassionate release of Abdelbaset Ali Mohmad Al Megrahi has become "imperative", according to MSP Christine Grahame, in the light of the revelation that any decision to send him to Libya under the prisoner transfer agreement could be subject to immediate judicial review by US relatives of those killed in the Pan Am 103 explosion.

US relatives of those killed, who near-universally retain the belief that Megrahi is guilty, are understood to be planning to block any prisoner transfer by way of judicial review, to ensure Megrahi's death in prison.

"This makes the case for compassionate release absolutely imperative," she said.

"That option is not subject to judicial review and is the only sensible compromise position in light of the fresh evidence and Mr Megrahi's deteriorating health. The likelihood of a drawn-out process resulting from a judicial review launched by US relatives would effectively condemn Mr Megrahi to die in prison. There has already been considerable delay which means that Mr Megrahi will not live to see the end of the appeal he has ongoing against his conviction.

"The weight of evidence which has emerged combined with the serious doubts raised over the original evidence that was led at the trial have left me in no doubt of Mr Megrahi's innocence."

US based relatives spokesman Dan Cohen, who lost his daughter Theodora in the incident, said in October 2008: “I want to see al-Megrahi die in jail.  If it's 20 years from now or if it's six months from now, then so be it  If it is true he has cancer then there is some small manner of justice in that.”

Cohen has been a long standing vocal proponent of the discredited Crown case against Megrahi.