Every year on December 21, Bob Monetti, like hundreds of other Americans, marks the anniversary of the Lockerbie bombing in a ceremony in Washington’s Arlington National Cemetery. A lone piper plays while family and friends gather around a 10ft-high memorial cairn, hewn from Dumfriesshire sandstone, to remember the 270 people who died when Pan Am flight 103 was blown out of the sky in 1988.

Last year marked the 20th anniversary of the bombing but for Monetti, whose son Rick was among the victims, the passage of time has done little to ease his pain. He draws some comfort from the fact that Abdelbaset Ali Mohmed alMegrahi, the man convicted of the bombing, is serving a life sentence in prison.

Like other American relatives of the victims, he has absolutely no doubt the former Libyan agent bought items of children’s clothing from Mary’s House boutique in Sliema, the Maltese capital, which he then wrapped around the bomb loaded onto the flight which exploded with catastrophic consequences over the Dumfriesshire town.

For Monetti and other American families who lost loved ones in the atrocity, justice has been done. “He is right where he belongs,” says the aviation security adviser from his New Jersey home.

In Scotland, opinion has moved on. In a country where there is regular coverage of the case, Megrahi’s guilt is no longer universally accepted and the debate is no longer about the merits of the case but whether he should be released. Of course the Appeal Court has yet to make its judgment, but few question that the crown’s case against Megrahi was flawed.

Added to that is the fact that he is dying from cancer and, far from being a public hate figure, as would be expected were he unquestionably guilty, public opinion is divided.

Last week the Libyan government applied for a prisoner transfer order that, if granted, would allow him to spend the rest of his sentence at a jail in his homeland. The order can only be granted if Megrahi drops an ongoing appeal against his conviction, which many now believe he has a good chance of winning.

Alex Salmond, the first minister, upon whose government the final decision rests, maintained last week that the decision would be purely a judicial one but many people are sceptical that this can be the case. The Lockerbie bombing was always a heavily politicised case and the dilemma now facing the Scottish government is this: does it take the compassionate decision to allow Megrahi home and in doing so to risk a public backlash, while also allowing the Crown Office to escape censure for what many believe was a botched, politically motivated prosecution? Or does it insist that the prisoner remains in jail until he dies or his appeal is finalised, thereby potentially compounding the sin of his incarceration and alienating Libya, with whom the UK is now building a constructive partnership?

Today Megrahi, wearing the grey and blue prison regulation tracksuit for all inmates of Greenock prison, is a shadow of the youthful looking former Libyan intelligence officer arrested in Tripoli in 1992. Prostate cancer has spread to other parts of his body and is at an advanced stage. The prescription painkillers he takes are not strong enough to stop him wincing when he talks in his strong north African accent of his desperation to see his family again before he dies.

He has only months to live, according to a consultant who recently examined him.

Megrahi, who is fluent in English, does not come across as embittered despite his claim to be a victim of a breathtaking miscarriage of justice. He does not trust the authorities, uncertain whether dropping his appeal would guarantee his return to Libya, most likely seeing out his final days under house arrest, or whether events may conspire against him.

If he agrees to drop the appeal, formally confirming his acceptance of guilt, could another terrorist attack yet make the transfer politically impossible, he wonders?

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