Lawyers acting for the Lockerbie bomber say a crucial prosecution witness expressed an interest in receiving a financial reward before he gave evidence which helped convict the Libyan of mass murder.
Abdelbaset al-Megrahi's legal team claim that Tony Gauci later received more than $2 million from the American authorities.
The lawyers have released hundreds of pages of submissions which would have been aired in court had Megrahi not decided to abandon his second appeal six weeks ago.
The Libyan, who is dying of cancer, has always protested his innocence and is now trying to win over public opinion. At his trial at Camp Zeist in the Netherlands, the prosecution alleged the bomb which destroyed Pan Am 103 and killed 270 people was held in a suitcase along with clothes bought at Mary's House, a shop in Malta.
The shopkeeper - Mr Gauci - told the trial Megrahi "resembled a lot" the Libyan who purchased the clothes before the bombing in 1988. The trial judges cited Mr Gauci's qualified identification of Megrahi as one of the reasons for the guilty verdict.
On Friday, Megrahi's legal team said there was "significant evidence" undermining Mr Gauci's credibility which was not disclosed at his trial, resulting in a miscarriage of justice.
They claim the Scottish Criminal Cases Review Commission found material which indicated that the shopkeeper had, at an early stage, expressed an interest in receiving payment or compensation for his cooperation in giving evidence.
They allege the US authorities offered to make substantial payments to Gauci from an early stage. They also suggest that Scottish Police applied for reward money from the US Department of Justice after the trial and that more than $2 million was given to Mr Gauci and more than $1 million to his brother, Paul.
Prosecutors at the Crown Office released a statement saying: "The only place to determine these issues is the criminal court.
"All of these issues could have been raised during the course of the appeal which Mr Megrahi abandoned. He had no reason to do so when his appeal did not interfere with his application for compassionate release."
In a further development on Friday, it has emerged that the Lockerbie trial judges have publicly denied they were under any pressure to find Abdelbaset al-Megrahi guilty of the mass murder of 270 people.
A spokesperson for Lord Sutherland, Lord Coulsfield and Lord MacLean was authorised to make the statement in a letter to the New York Times.
The respected US newspaper had published a claim from Dirk Vandewalle, an associate professor of government at Dartmouth College, that one of the judges told him during a conversation that "there was enormous pressure put on the court to get a conviction."
The judges' letter was written by Elizabeth Cutting, public information officer for the Scottish Judiciary. In it, she says: "I’m authorized to say that to the best of their knowledge the three deciding judges on the panel — Lord Sutherland, Lord Coulsfield and Lord MacLean — have never met Mr. Vandewalle.
"Moreover, they assert that none of them has ever said what Mr. Vandewalle reports one of them to have said. They were never under any pressure to return any particular verdict."
All three judges have retired. This is thought to be their first joint statement since they delivered their verdicts in 2001.
A senior Scottish QC told STV News: "There have been occasions in the past when there has been some public comment from a judge either directly or indirectly, but something like this is very, very, very rare.
"In the 40 years of my career I can't remember anything like this at all.”
