A Roman Catholic priest who witnessed the aftermath of the Lockerbie bombing today called for the release of the man convicted for it.

A Roman Catholic priest who witnessed the aftermath of the Lockerbie bombing today called for the release of the man convicted for it.

Father Patrick Keegans said Libyan national Abelbaset Ali Mohmed Al Megrahi was innocent of the crime and also deserved release on compassionate grounds.

Megrahi, serving a life sentence in Greenock prison, has been diagnosed with prostate cancer.

Defence lawyers last month lost a court attempt for him to be freed on bail pending an appeal expected to take place some time next year.

Fr Keegans, 62, today gave his support to a campaign to have him released from prison on compassionate grounds.

The campaign is being led by Jim Swire, whose daughter Flora was among the 270 people killed in the 1988 bombing of a PanAm jumbo jet, which was brought down over Lockerbie.

Fr Keegans told a Glasgow press conference: "I'm here today because of my conscience."

He said he had not so far sought publicity but had been moved this week by newspaper accounts of Megrahi's wife and family.

They are staying in Glasgow in order to be able to visit him in prison.

"My conscience has moved so much over the past two days that I wrote to Mr Megrahi offering him my support, telling him that I was convinced he is innocent and that I would willingly offer support to him and his family," said the priest.

Fr Keegans said that that view put him at odds with friends in the US - many of whom were "convinced" of the Libyan's guilt.

"If I was convinced of Mr Megrahi's guilt, I would not be here today," he said.

"I'm here today because of his human plight, I'm here because I believe Scotland is a compassionate and a fair country.

"I also believe that justice for Mr Megrahi will equal justice for the families because the full truth of Lockerbie has never been revealed."

Fr Keegans, who now lives in Ayr, was a priest in Lockerbie at the time of the bombing.

Mr Swire said the priest lived on the edge of the Sherwood area of the town, where the fuel-laden wing section of the Boeing 747 came down.

"His house was shaken as if there had been an earthquake, the world was lit up, and the first thing he had to do was calm his mother," said Mr Swire.

"When he opened the door he saw a vision of purgatory, of hell, because that's where the crater was."

Although Megrahi lost his court bid for bail, it still remains open to his family to apply to Scottish ministers for his release on compassionate grounds.

Mr Swire, who today visited Megrahi in prison for the second time, said the campaign will include approaches to enlist the support of MSPs in the Scottish Parliament and approaching ministers to seek his release pending the appeal.

Mr Swire said he noticed a change in Megrahi's appearance.

"He is clearly a man who is not physically well," he said.

He paid tribute to Megrahi's family for their loyalty, which had extended to the Libyan's daughter deciding to get married in Barlinnie prison in Glasgow at the time her father was held there.

"We need to try to put ourselves in the position of a man who is 1,000 miles away from his home country, who separated from his family whom he loves dearly and who love him dearly, and who has been told he has only months to live.

"He has proclaimed throughout the last 15 years since he has been brought to the court that he is innocent."

Mr Swire, a retired GP who has long argued that Megrahi is innocent, said: "He is in a desperate human situation - put yourself into that position and see what it would be like."

Fr Keegans said he had long been "concerned" about the Lockerbie case.

Supporters of the newly launched campaign include Ian McKie, whose daughter Shirley, a former policewoman, accepted £750,000 from the then Scottish Executive in 2006 after a long-running legal battle over fingerprint evidence in an Ayrshire murder case.

Mr McKie said his son, Stuart, was one of the first police officers on the scene in Lockerbie and has never recovered.

The campaign group plan to mark the 20th anniversary of the disaster later this month with a service in the chapel of Heathrow Airport.