A copy of an alleged confession by the Libyan accused of building the bomb that brought down an American airliner over Lockerbie 38 years ago can be used at his trial, a US judge has ruled.

Abu Agila Mas’ud Kheir Al-Marimi, 74, has claimed he was forced by three masked men into making a false confession while in custody in Libya.

Masud’s lawyers asked a federal court in Washington to rule the alleged confession inadmissible in advance of his trial in April next year as it was not the original document.

But Judge Dabney Friedrich denied the motion, meaning it can be used in evidence.

The accused, dressed in a green prison jumpsuit, was in court where he listened to proceedings through an interpreter.

Mas’ud has denied building and priming the bomb that brought down Pan Am Flight 103 over Lockerbie on 21 December 1988, killing 270 people.

He has insisted that the masked men men ordered him to memorise information about the destruction of Pan Am 103 and another terror attack.

Mas’ud said he repeated what he had learned to a Libyan official, under duress, after the men threatened his family.

He has also claimed he was illegally removed from Libya to stand trial in the United States after “a cloak and dagger operation conducted in the dead of night”.

Details of the alleged confession were first made public five years ago, after the US department of justice announced it was charging Mas’ud over the Lockerbie bombing.

A criminal complaint summary compiled by the FBI claimed he had admitted playing a key role in the attack when he was in detention in 2012, following the collapse of Colonel Gaddafi’s regime the previous year.

The FBI has said the Libyan official who noted Mas’ud’s confession in 2012 is prepared to give evidence at his trial.

Of the 259 passengers and crew who died on board the airliner, 190 were from the United States, where the Mas’ud case will be tried.

The only Lockerbie trial so far took place between May 2000 and January 2001, when three Scottish judges convicted Libyan intelligence agent Abdulbasset al-Megrahi of playing a key role in the plot.

Megrahi was jailed for life but released on compassionate grounds by the Scottish government in 2009 after he was diagnosed with terminal cancer. He died three years later at home in Tripoli.