Ministers on Monday faced renewed pressure over the early release of the Lockerbie bomber after a former British ambassador to Libya said he suspected a “political deal” lay behind the contentious move.

Oliver Miles said there was “mystery” surrounding the decision by Abdelbaset Ali Mohmed al-Megrahi to drop his appeal against his conviction for the Lockerbie bombing. Mr Megrahi was last month released on compassionate grounds after serving eight years of a 27-year sentence imposed for murdering 270 people in the 1988 bombing of Pan Am flight 103.