A new witness is expected this week to undermine thoroughly the case against the only person to be convicted of the Lockerbie bombing. New testimony will call into question evidence linking the Libyan Abdel Basset Ali al-Megrahi to the bomb that blew up Pan Am Flight 103 in 1988, his lawyers claim.
Megrahi, who has terminal cancer, is serving 27 years in Greenock prison for the bombing.
Appeal hearings are due to begin on Tuesday, and Megrahi's lawyers insisted this weekend they will go ahead as planned, despite speculation that he may be returned to Libya under the terms of a controversial prisoner transfer agreement, due to be ratified tomorrow.
"We are turning up next week," said Tony Kelly, his solicitor. "We are seeking that the court upholds his appeal, admit that there has been a miscarriage of justice, and grant him his liberty. Whatever remedies come after that is for after the appeal."
Appeal documents seen by The Independent on Sunday reveal that testimony from a new witness is expected to undermine the evidence of a key prosecution witness, Tony Gauci, a Maltese shopkeeper. His testimony was vital in connecting Megrahi to the bombing at the trial in 2001.
Mr Gauci identified Megrahi as the person who bought the tweed suit, baby sleepsuit and umbrella found among the remnants of the suitcase that contained the bomb on board.
The new witness, not named in the documents, will provide an account the defence claims is "startling in its consistency with Mr Gauci's account of the purchase, but adds considerable doubt to the date the key items were purchased and identification of Megrahi as the purchaser".
All of this may be academic, as 56-year-old Megrahi, who was diagnosed with advanced prostate cancer in October 2008, has been reported as having less than a year to live and the appeal could take two years.
Increasingly, however, it seems likely that the Lockerbie suspect will spend his last days in Libya. This month, officials wrote to the families of victims of the bombing explaining the prisoner transfer programme, interpreted as a tacit agreement that Megrahi may be returned to Libya. Under the terms of the deal, if Megrahi participates in the transfer scheme, he will forfeit his right to appeal.
"If he goes back to Libya, it will be a bitter pill to swallow, as an appeal would reveal the fallacies in the prosecution case," said Dr Jim Swire, whose daughter Flora was killed on Flight 103. Dr Swire is a member of UK Families Flight 103, which wants a public inquiry into the crash. "I've lost faith in the Scottish criminal justice system, but if the appeal is heard, there is not a snowball's chance in hell that the prosecution case will survive."