The appeal of the man convicted of the Lockerbie bombing has been so significantly delayed that he may not live to see its conclusion, his defence team has warned.

The appeal of the man convicted of the Lockerbie bombing has been so significantly delayed that he may not live to see its conclusion, his defence team has warned.

The appeal, which has already been put back due the non-disclosure of scores of documents, will now not resume until at least September as one of the judges has had heart surgery.

Lord Wheatley, one of five judges at a lengthy hearing in May that dealt with the first part of the appeal by Abdelbaset Ali Mohmed al Megrahi, the Libyan convicted of the atrocity, is recuperating from surgery and will not be fit to resume judicial duties until mid-September.

Lord Hamilton, the Lord Justice General, told the court yesterday that the situation "complicates matters" and that his convalescence may be "protracted".

The delay makes it all the more likely that Megrahi, who is suffering terminal prostate cancer, will feel forced to drop his appeal to allow him to return to Tripoli.

The Libyan government applied for prisoner transfer of Megrahi in May and Justice Secretary Kenny MacAskill has 90 days to make a decision. The transfer can not go ahead while legal proceedings are live.

Lord Hamilton said that although the court had already heard full submissions on two grounds of appeal, they would not now be able to give a decision on those grounds until the autumn.

Margaret Scott, Megrahi's QC, acknowledged that it arose out of "unforeseen and unexpected" circumstances.

She told the court the defence wished to see a decision reached as soon as possible and requested they consider appointing a shadow judge to avoid such problems in future.

"My Lord will appreciate in this case justice delayed is justice denied," she said. "There is a very real risk my client will die before this appeal is adjudicated."

She added that it was difficult to conceive of "more pressing circumstances".

Ms Scott told the court that her client's health was deteriorating and he was experiencing a "relentless onset of symptoms".

Lord Hamilton said he recognised that Megrahi was "anxious" to have a decision as soon as possible, and would have wanted a decision on two grounds yesterday.

But the judge said that "regrettably" the court was not able to do so.

"It is only when Lord Wheatley is fit to resume judicial duties that it will be possible to resume consultation among all the judges with a view to reaching a final decision," he said.

He agreed to consider a defence plea for a "shadow judge" to be appointed to sit in any future hearings not attended by Lord Wheatley.

Dr Jim Swire, whose daughter Flora died in the tragedy, said he was utterly dismayed by the repeated delays in the appeal. He wants ministers to consider allowing Megrahi to return to Libya on "compassionate grounds" rather than through prisoner transfer, to allow the appeal to continue in his absence.

Christine Graham, SNP MSP, 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.

"Given the further significant delay announced today by the Crown Office I believe the case for proceeding with this option, compassionate release, is now overwhelming."