He was the only man found guilty in 2001 of blowing up Pan Am flight 103, which killed two hundred and seventy people on the evening of December 21, 1988.
Over the fourteen years since his conviction, the case against him presented by advocates of the Scottish Crown Office has steadily fallen apart.
It is now known and scientifically proven that supposedly damning evidence against Megrahi relied on concealment by senior police officers of key facts supporting the defence case, and presentation of false scientific data by a senior British forensic scientist.
Long-time campaigner Dr Jim Swire, whose 23-year-old daughter Flora was killed in the bombing, yesterday said: “After I realised that he had nothing to do with the murder of my daughter, Megrahi became my friend. There are a lot of legal people in Scotland who want to see this issue properly resolved. I hope that the appeal will succeed and, when it does, Megrahi’s family will no longer be regarded as the family of the so-called Lockerbie bomber. ”
This will be the third time Megrahi’s conviction has been the subject of an appeal.
After he received his life sentence in 2001, Megrahi appealed but his appeal was unsuccessful.
A second appeal saw the Scottish Criminal Cases Review Commission (SCCRC) refer the case back to the Scottish High Court, suggesting that there “may have been a miscarriage of justice” and it was “in the interests of justice” to look at the case again.
But in 2009 Megrahi - by then suffering from terminal prostate cancer - abandoned his second appeal to improve his chances of being allowed to go home to Libya. He died on 20th May 2012.
Whenever in the past the prosecution evidence on which his conviction was based has been challenged by new information or scientific experiments, the Scottish Crown Office comment has been that these matters can be properly examined only in a court of law.
A third appeal means that they will be. It will give the Megrahi defence team an opportunity to present the new evidence, and cross-examine current and former police officers and forensic scientists.