Exclusive: Dr Jim Swire, whose daughter died in the Lockerbie bombing, has written an open letter to the Justice Secretary pleading with him to release the man convicted of the atrocity on compassionate grounds to allow the appeal to continue.

Dr Jim Swire, whose daughter died in the Lockerbie bombing, has written an open letter to the Justice Secretary pleading with him to release the man convicted of the atrocity on compassionate grounds to allow the appeal to continue.

Following a meeting on Monday between Kenny MacAskill and three relatives of victims to discuss the fate of the Libyan convicted of the bombing, Dr Swire has asked the minister to find a way of allowing the judicial process to continue.

He wrote: "To allow the appeal to be abandoned would be a body blow to the international reputation of Scotland and to domestic confidence in our judicial system for a generation."

The minister is considering an application for the transfer to Libya of Abdelbaset Ali Mohmed al Megrahi, who is suffering from terminal prostate cancer.

It is not known if Megrahi, who is currently serving 27 years in Greenock for the bombing, will last the appeal process. Despite his health, the next stage of the appeal, which is expected to undermine the credibility of Tony Gauci, the Crown's key witness, is now not due to begin until the autumn.

A procedural hearing will take place next week to discuss why the Crown has still not shared certain documents and evidence with the defence.

Megrahi would have to drop the appeal in order for the Prisoner Transfer Agreement (PTA), a move thought favourable to key agencies in the UK and US.

Dr Swire's letter states: "To use the PTA would be to stop the second appeal and would cost our country the best chance of showing that it can objectively assess its own past performance and if necessary be brave enough to correct it from within, even in the face of gross international pressures.

"It would also grievously damage the search by innocent relatives for the truth concerning the murders of their dear families."