Lawyers acting for the Lockerbie bomber have warned he could die before a final decision is made on his appeal.

Abdelbaset al-Megrahi is terminally ill with cancer and his lawyers say his condition is deteriorating.

The case is facing further delays after one of the Appeal Court judges had to undergo heart surgery.

Scotland's top judge, the Lord Justice General Lord Hamilton, told the High Court in Edinburgh that Lord Wheatley's recuperation may be "protracted" and it is thought he will not be fit to resume judicial duties until mid-September.

SNP MSP Christine Grahame the case for returning the terminally-ill Libyan home was now "overwhelming". Al-Megrahi's QC, Margaret Scott, also expressed dismay at the situation, but acknowledged it arose out of "unforeseen and unexpected" circumstances.

She told the court the defence wished to see a decision reached as soon as possible. "My Lord will appreciate in this court justice delayed is justice denied," she said. "There is a very real risk my client will die before this appeal is adjudicated." The court heard that that al-Megrahi's health was deteriorating and he was experiencing a "relentless onset of symptoms".

Ms Grahame, the SNP member for the South of Scotland, said: "It is within the powers of the Justice Minister and the Scottish Government to return Megrahi to Libya on compassionate release. This does not require a formal application from the prisoner."

She added: "I believe the case for proceeding with this option, compassionate release, is now overwhelming. That would allow Mr Megrahi's appeal to continue and further ensure that Scottish justice is responsive to the nature of his terminal illness."

Ms Grahame, who has had recent meetings with Al Megrahi in Greenock prison, said the whole process had been hit by "extraordinary delay".

Dr Jim Swire, whose daughter Flora was killed in the bombing said he believes al-Megrahi should be sent home to Libya as soon as possible on compassionate grounds

He said: "Because I know the man and because I'm satisfied that he's innocent, I would like to see Mr Megrahi go home to his people, and his family in particular in Tripoli, as soon as possible. I don't think his continuing detention here adds anything to the judicial process."

Speaking outside court, he said he hoped another judge would be appointed to avoid any further delay.

"In the background is the terrible ongoing process of the appellant's illness. What state the appellant will be in by September, I don't know," he said.

Al-Megrahi, currently being held in Greenock Prison, was diagnosed with prostate cancer last year.