The Scottish government’s decision to release Abdelbaset Ali Mohmed al-Megrahi on compassionate grounds has reawakened memories of the Lockerbie tragedy and raised fresh doubts about the merits of his conviction.

Mr Megrahi, 57, was serving a 27-year sentence for the murder of 270 people, most of them American, when Pan Am flight 103 was blown up in 1988 over the Scottish town of Lockerbie.