A grievous miscarriage of justice – described by some as the worst in British legal history – may have occurred in the conviction of Abdelbaset al-Megrahi for the Lockerbie bombing, the Scottish criminal cases review commission has found.

The SCCRC approved an application to refer Megrahi’s conviction back to the appeal court on Wednesday following an application by the lawyer Aamer Anwar on behalf of Megrahi’s family. The application was supported by some families of those who died in the 1988 disaster.

Megrahi was convicted in 2001 of the Lockerbie bombing, the only person found guilty of the atrocity. He was sentenced to 27 years in prison but died of prostate cancer in 2012 aged 60 after being released in 2009 on compassionate grounds.

The Pan Am flight 103 was on its way from London to New York when it exploded above Lockerbie on 21 December 1988, killing 243 passengers and 16 crew on board. The debris that landed in and around the town of Lockerbie caused the deaths of a further 11 people. In all, 270 people from 21 countries were killed in one of the worst terrorist atrocities committed in the UK.

“A reversal of the verdict would have meant that the government of the United States and the United Kingdom stand exposed as having lived a monumental lie for 31 years, imprisoning a man they knew to be innocent and punishing the Libyan people for a crime which they did not commit,” Anwar said.

Anwar told a press briefing that the commission had delivered “a damning indictment of the process”. He said that as a result of the case, “the reputation of the Scottish criminal justice system has suffered badly both at home and internationally because of the widespread doubts about the conviction” of Megrahi.

Lawyer Aamer Anwar speaks to the media at the Marriott Hotel, Glasgow. Photograph: Andrew Milligan/PA

Anwar said the “unprecedented” collaboration between the Megrahi family and some of the families of the victims who died working together spoke volumes. He added that both sides had welcomed the decision.

In a statement, Ali al-Megrahi, the son of the applicant, said: “Finally, my family has hope that our father’s name will be cleared. I am grateful to all those who have supported my family in their long struggle for justice.”

Speaking of Megrahi, Anwar said: “His children lost their childhood. They carry a stain of having the name of the man convicted of the worst murder in the UK. And when the name Megrahi is mentioned, people always attach to them that they are relatives of the Lockerbie bomber. Ali al-Megrahi said to me that his father went to his grave still with the wish for justice on his lips – those were his final words.”

Dr Jim Swire, the father of Flora Swire, who died the day before her 24th birthday, said: “It has always been and remains my intent to see those responsible for her death brought to justice. I still ache for her, what might have been, the grandchildren she would have had, the love she always gave us and the glowing medical career.”

Megrahi’s lawyers maintain that he was the victim of one of the worst miscarriages of justice in British legal history. They say Iran has long been suspected of being behind the attack, ordering a Syrian-Palestinian group to carry out a revenge attack for the downing of an Iranian Airbus flight 655 by the US Vincennes on 3 July 1988, which killed all 290 on board.

“Many people said to us: ‘What is the point?’ Well, I suggest that those people who think there is a time limit on justice should speak to the family members who have lost their children and should speak to the family of Megrahi, because they describe him as the 271st victim,” Anwar said.

The legal team submitted six grounds why the Megrahi case constituted a miscarriage of justice. The commission upheld two of the grounds, concluding a miscarriage of justice may have occurred by reason of an “unreasonable verdict”, which allows an appeal on the basis that a conviction was based upon a verdict that no reasonable jury could have returned, and on the ground of “non-disclosure”.Anwar’s team submitted a number of allegations of the failure of the crown to disclose evidence, which could have been key to the defence and interfered with the right of a free trial

In 2014, Anwar lodged an application with the SCCRC seeking to overturn the conviction on behalf of Megrahi’s family and the families of some of those who died. The appeal court ruled in 2015 that the families would not be allowed to pursue an appeal. In 2017, a further application was lodged with the commission.