Justice Secretary Kenny MacAskill insisted that a medical report on the life expectancy of the Lockerbie bomber was accurate.

He told Parliament that those waiting for Libyan Abdelbaset Ali Mohmed Al Megrahi to die were "circling like vultures".

Mr MacAskill granted compassionate release last August after Megrahi was diagnosed with terminal prostate cancer.

Labour MSP Lord Foulkes and Tory justice spokesman Bill Aitken questioned the minister about Megrahi's health.

Lord Foulkes, a Lothians MSP, asked the Justice Secretary to update Parliament on Megrahi's condition, "almost six months after his release".

Mr MacAskill said Libyan government medical reports on Megrahi were reported widely in the press.

He said: "It's not in any doubt that this is a dying man and, I have to say Lord Foulkes, I think it ill-befits us in the name of humanity to circle like vultures. He is going to die. That is why he was released."

Mr Aitken said the decision to release Megrahi on compassionate grounds was based on medical evidence prepared in July last year.

He said: "The point is that Mr Megrahi is still with us."

He then asked the minister if he had "any reasons for questioning the accuracy of that medical evidence".

Mr MacAskill replied: "No. I made it quite clear when I released Mr Al Megrahi on compassionate grounds that he may die sooner or he may die later. The evidence provided by the director of health and social services for the Scottish Prison Service said that if he remained in a Scottish prison it was likely he would die within the period of three months.

"It's a self-evident fact that he had lived beyond that. It's also quite clear from the medical information provided, paraded across papers the length and breadth of Scotland and indeed elsewhere, that he has been receiving chemotherapy.

"That in fact was not recommended by Scottish doctors on the basis that it would not serve to tackle the underlying problem.

"He is doubtless receiving an increase in life expectancy but no doubt at the cost of the quality of life he is having in his last few days."