Leading article: Come clean over this miscarriage of justice

Expectations are growing that Abdelbaset Ali al-Megrahi, the Libyan found guilty of perpetrating the 1988 Lockerbie bombing, will be permitted to return to Libya next week.

Al-Megrahi was diagnosed last year with terminal prostate cancer. The Scottish Government seems to have bowed to pressure from Tripoli for him to be allowed to return home to Libya to die. It is not yet clear whether this release will be authorised on compassionate grounds, or whether it will be a formal prisoner transfer. Either way, allowing al-Megrahi to return home is the right decision.

The response from the relatives of those 270 civilians who died in the bombing of Pan Am Flight 103 has been divided. Dr Jim Swire, the unofficial spokesman of the British families whose relatives died when the plane crashed to the ground over the small Scottish town, yesterday welcomed the prospect of al-Megrahi's release. But the US families of those who died on the flight have expressed their anger about the move, with several accusing the UK and US governments of putting their desire to maintain good relations with Libya ahead of concerns about justice. The Libyan leader, Colonel Muammar Gaddafi, who has been pushing hard for al-Megrahi's transfer, is without doubt a repellent figure. For more than four decades he has locked up opponents, murdered dissenters and even sponsored terrorist attacks abroad. There is also something distasteful about the haste with which Western governments have rushed to embrace him since Libya agreed to dismantle its nuclear programme in 2003.

Yet the fact is that this particular agreement does not look like a Western attempt to curry favour with the Libyan regime. It is doubtful whether al-Megrahi should have been convicted in the first place. Al-Megrahi is unlikely to be a saint, having worked for the Libyan intelligence services for a number of years. But the evidence linking him to the Lockerbie bombing has looked increasingly weak since his conviction in 2001.

In that trial, held in a specially convened court in the Netherlands, al-Megrahi was positively identified by a witness who, it has been alleged, was offered a $2m reward for his evidence. The Libyan's defence team was also, apparently, denied access to official government papers that were made available to Scottish police. Furthermore, evidence has emerged that the Iranian regime sponsored the bombing. One former Iranian agent has come forward to claim that it was revenge for the shooting down of an Iranian commercial airliner by a US warship in July 1988. Taken together, all this provides serious grounds for believing that a miscarriage of justice took place.

Some doubt whether we will ever discover conclusive proof of who was responsible for the mass murder in Lockerbie, arguing that too much time has passed. But it would be wrong simply to give up trying to discover what happened. Even if al-Megrahi is permitted to return to Libya to die, his appeal against his conviction should run its course. The evidence against him – and the Libyan state – must be thoroughly tested.

So much about this tragedy remains shrouded in shadow. If it cannot be dragged into the light, we should at least attempt to establish what we do not know. And if the wrong individual was convicted for this terrible crime, the authorities must not be allowed to sweep that uncomfortable fact under the carpet.