The UK Government has been asked to set aside data protection rules to allow the release of more details about the Lockerbie bomber's abandoned appeal against conviction.

Abdelbaset al-Megrahi gave up his legal challenge shortly before he was released on compassionate grounds from Greenock jail in 2009.

He was serving a sentence for the murder of 270 people in the bombing of Pan Am flight 103 in December 1988.

The Scottish Criminal Cases Review Commission (SCCRC) had said he was entitled to an appeal, but said it had no power to make its reasons available to the public, prompting the Scottish Government to make a pledge to change the law.

Scottish Justice Secretary Kenny MacAskill, who published the Criminal Cases (Punishment and Review) Bill on Thursday, has written to his Westminster counterpart Ken Clarke to make further changes.

Mr MacAskill said: "The Bill puts in place a framework that will enable, as far as possible within devolved competence, the disclosure of information by the SCCRC in cases where an appeal has been abandoned or has fallen.

"This Government continues to do all we can to achieve publication of the statement of reasons in the al-Megrahi case, while of course we cannot legislate on reserved matters.

"That is why I have today written to the UK Government asking that they set aside data protection legislation, freeing the commission from this obstacle in deciding whether they will publish information.

"We believe there is a compelling and genuine public interest justification for making an exception to data protection legislation in this case and that such an exception would not set a wider precedent.

"The Scottish Government does not doubt the safety of the conviction of Mr al-Megrahi. Nevertheless we recognise that others have concerns regarding the wider issues relating to the atrocity and given the massive public interest in the case I believe it is right that the commission's statement of reasons is released."

Public interest

The SCCRC decided in June 2007 that Megrahi could have a second appeal against his conviction.

But in August 2009 three judges at the High Court in Edinburgh accepted his bid to formally drop the appeal amid growing speculation that he could be freed within days.

Mr MacAskill accepted the application for compassionate release later that month after being told the Libyan was close to death from cancer.

In his letter to Mr Clarke, Mr MacAskill described data protection as a potential obstacle to the full release of details.

He wrote: "We are, of course, well aware that data protection legislation exists for a purpose and that is not to be put aside lightly.

"However, as the publication of a previously unprecedented level of documents and records by both the UK and Scottish governments has shown, the al-Megrahi case is in many ways unique.

"We believe there is a compelling and genuine public interest justification for making an exception to data protection legislation in this case and that such an exception would not set a wider precedent."

The new Bill is not limited to the Lockerbie case, also covering a second area of the Scottish criminal justice system.

The Scottish Government wants to resolve an anomaly following an Appeal Court judgment which meant criminals serving discretionary life sentences could challenge the minimum term they spend in jail.

The law was examined after rapist Robert Foye and paedophile Morris Petch lodged appeals against the punishment part of their sentence - the term they must serve before being considered for release on licence.

The Bill, which is not retrospective, will give courts discretion to set punishment parts for sentences.

Mr MacAskill said: "The Petch and Foye judgment introduced an absurd situation where prisoners serving life sentences were able to qualify for parole earlier than those not serving life.

"No sensible person would endorse that approach. Appeal judges who made the ruling called on the Scottish Parliament to intervene with 'a clear, well-considered legislative solution' and I call for all parties to unite behind this Bill and correct this legal anomaly."