As a result of the commission’s decision, Mr Megrahi’s family is now entitled to instruct an appeal against his conviction on 31 January 2001 for the murders of the 243 passengers and the 16 crew on board Pan Am Flight 103 (PA 103) from London to New York, and 11 residents of Lockerbie, on 21 December 1988.

The commission has sent a statement of reasons for its decision to the High Court. It has sent a copy of the document to the family’s solicitors, Aamer Anwar & Co, the Lord Advocate and the Crown Agent.

Announcing the decision today, the chairman of the commission, Bill Matthews, said: “We recognise that the commission plays an important role in the Scottish criminal justice system and has extensive statutory powers to enable it to carry out its duties. This is the second time that the commission has carried out what I believe has been a rigorous and independent review of this particular conviction, and we note that since our last review further information has become available, including within the public domain, which the commission has now been able to consider and assess.

“As the chair of the SCCRC in 2007 said when the case was originally referred, our function is not to decide upon the guilt or innocence of an applicant. Our function is to examine the grounds of review identified and to decide whether any of the grounds meet the statutory test for a potential miscarriage.

“I am pleased therefore that we are now able to issue a detailed statement of reasons which addresses all of the issues raised. I am satisfied that the matter is now returning to the appropriate forum – the appeal court – to consider fully all of the issues raised in our statement of reasons.”

Gerard Sinclair, the chief executive of the commission, said today: “When we referred this case in 2007 I never expected that, over 10 years later, we would be asked not only to revisit our original decision, applying the law as currently stated, but also consider a whole new set of materials which had become available in the intervening years. I’m pleased to report that, after another lengthy investigation and review, we are now in a position to issue our decision in this unique case.

“It seems important to note that, this month, an entirely new board of the commission from that which considered the matter in 2007 has again decided to refer this case. The 419-page decision issued today, with voluminous appendices, is a testament to the hard work and diligence of our investigating team over the last 3 years, involving us in novel and challenging court procedures along the way, and I pay tribute to them.

“The commission’s involvement in the case is, once again, at an end. It is now a matter for those representing the Crown and the defence to decide how to proceed at any future appeal. Thereafter, it will be for the appeal court to decide whether there has been a miscarriage of justice in this case.”