The health of the Lockerbie bomber has "not deteriorated" since his release from prison three months ago – despite doctors' assessments that he would have died by now, a senior source has told The Sunday Telegraph.

The disclosure will reignite the row over the release of Abdelbaset Ali Mohmed al-Megrahi on compassionate grounds despite his conviction for the murder of 270 people when Pan Am flight 103 exploded in mid-air over Lockerbie in 1988.

Megrahi, who is suffering terminal prostate cancer, was sent home to Libya to die after medical experts concluded in a report on July 30 he had just three months left to live. The time span was crucial because only prisoners with three months or less to survive are eligible for release on compassionate grounds.

But three months on from Prof Sikora's diagnosis, Megrahi is well enough to "walk and talk" and shows no sign of deterioration, according to a senior source involved in his release.