It was carried out by Palestinian terrorists based in Syria, he says, and not on the orders of Libyan dictator Muammar Gaddafi. The atrocity killed 243 passengers, 16 crew and a further 11 people on the ground in Lockerbie.

Ex-spy Abolghassem Mesbahi claims in a documentary aired tonight on Al Jazeera that former Iranian leader Ayatollah Khomeini wanted to mirror the 1988 US strike on an Iranian Airbus and recruited a Syrian-based group to plan an attack.

Mesbahi, who defected to Germany in the 1990s, said that the supreme leader, who died in 1989, wanted revenge.

He told documentary makers from Al Jazeera: ‘Iran decided to retaliate as soon as possible. The decision was made by the whole system in Iran and confirmed by Ayatollah Khomeni.