A former CIA agent says Iran is the real culprit behind the Lockerbie bombing.
John Holt was the US intelligence officer handling the inquiry’s star witness, Libyan double agent Abdul-Majid Giaka, but he was never called to the hearing.
Mr Holt claims attempts were made to detract attention from Iran and focus on Libya.
"I have reason to believe there was a concerted effort, for unexplained reasons, to switch the original investigations away from Iran and its bomb-making Palestinian extremist ally the PFLP General Command," he told The Telegraph.
“Now we should focus a new investigation on the Iranians and their links with the bomber.
"I would start by asking the current Attorney General William Barr why he suddenly switched focus in 1991, when he was also attorney general, from where clear evidence was leading, to a much less likely scenario involving Libyans."
Pan Am Flight 103 was blown up over the Scottish town of Lockerbie in December 1988 on its journey from London to New York killing 270 people, mostly Americans on their way home for Christmas.
Libyan intelligence officer Abdelbaset Al Megrahi was jailed for life in 2001 after being found guilty of the murder of 243 passengers, 16 crew and 11 residents of Lockerbie who died in the attack.
He is the only person to be convicted over the bombing.
Al Megrahi, who denied involvement, died in Libya in 2012 after being released three years earlier by Scotland's government on compassionate grounds after a diagnosis of terminal cancer.
In March, an independent Scottish review body ruled his family could launch an appeal after concluding there might have been a miscarriage of justice.
The Scottish Supreme Court is now considering whether to quash the conviction.
Mr Holt said Mr Giaka had a history of "making up stories" and during his time as his handler he never mentioned Libyan involvement in the bombing. He also claimed Mr Giaka bore a grudge against Al Megrahi.
"Whatever the Scottish Supreme Court decides, Britain should reopen the whole Lockerbie saga, have a heart to heart with the Americans, and go after Iran," he said.
"I have reason to believe that the three security agencies of the US government were working on evidence pointing directly to Iran, before the Libyan connection was brought into play.
"I believe the US government tried to hide evidence for political reasons, and Britain also was willing to go along with this.
"We now all need to admit we got the wrong man and focus on the real culprits."
A 419-page report in March found that new information still pointed to “Libya, and Megrahi as an operative in 1988 for that state, as being the culprits in the bombing of PA 103”.
But it said the failure of prosecutors to disclose that the US government had paid a key witness, and questions over the identity of Al Megrahi as the man who bought items packed inside the suitcase that contained the bomb, meant the case should go to appeal.
In 2003, Libyan leader Muammar Qaddafi accepted his country's responsibility for the bombing and paid compensation to the victims' families, but did not admit to personally ordering the attack.
Al Megrahi's family and some relatives of the Scottish victims have always doubted the convicted man’s guilt.
