Ashton says he is in no doubt that Scotland got the wrong man when Megrahi was convicted of the bombing of Pan Am Flight 103 in December 1988 which instantly killed the 259 passengers and crew aboard the plane and another 11 in the town of Lockerbie below.
Ashton also believes that those responsible for the bombing may never be brought to justice and calls the trial and conviction the "biggest scandal of Scotland's post-devolution era" and an act that "disgraces Scotland's criminal justice system".
He says the evidence still held by the Scottish Criminal Cases Review Commission (SCCRC), which investigated the conviction as a possible miscarriage of justice, should be made public.
The SCCRC found six grounds on which Megrahi's conviction was potentially unsafe. Both Megrahi and the Scottish Government want publication of the 800-page report in the interests of transparency, but this is subject to data-protection law which is reserved to Westminster.
That means approval has to be given by the key players in the case, including Megrahi, the Crown Office, Dumfries and Galloway Police, and witnesses including the Maltese shopkeeper Tony Gauci whose evidence linking Meghrai to the bombing has been questioned.
QUESTION: Is Megrahi blocking the publication of the Scottish Criminal Cases Review Commission report which recommended that his case be returned to the Appeal Court in 2007? If not, who is?
answer: No. His position is that everything must be published and he says he will allow everything over which he has a say to be published. He is happy for the evidence that doesn't stand in his favour to come out as well. His line is everyone should put out all the evidence. His beef is that 20 years after he was indicted, they are still withholding stuff.
Q. Has Megrahi ever said who was responsible for the Lockerbie bombing, or who he thinks did it?
A. No. And he won't. Because it was nothing to do with Libya. There was a lot of circumstantial evidence pointing towards a Palestinian cell in Germany. But he's very clear on this. He said he has been wrongly accused and it could be they have been as well. His line is we have to concentrate on disproving the evidence against him not on proving it against others. It is for the police to find the people who really did it, not for him and his legal team.
Q. Did he have any – even tangential – involvement or foreknowledge of the bombing?
A. No. That's my belief and that's what he says.
Q. So if he is to be believed, we have mass murderers on the loose that have not been dealt with in over 20 years. Has Megrahi ever raised any questions over seeking the real culprits?
A. He has sympathy for the bereaved and thinks they have been cheated. But he is very reluctant to point fingers, purely because of his own experience of being wrongly fingered.
Q. What about Megrahi's longevity despite being given a few months to live because of his prostate-cancer diagnosis?
A. The medical evidence was that the three months [to live] was a realistic prognosis. But clearly there was pressure on here. The Scottish Government as well as the UK Government, as well as the Libyans – everyone – was desperate for confirmation that he might only have a few months to live. It was a political fix, wasn't it? But that's not to say there was any dishonesty on the part of the doctors.
Q. What proof is there that during a meeting between Libyan diplomat Abdulati al-Obeidi and Justice Secretary Kenny MacAskill on August 10, 2009, a suggestion was made that it would be easier to gain compassionate release if Megrahi dropped his appeal? In what circumstances did MacAskill have this conversation?
A. The story is that Obeidi who led the Libyan delegation went for meetings with MacAskill and officials, and after that they went to the prison to see Megrahi. Obeidi later said to Megrahi that, during the meeting or at the end of the meeting, MacAskill had taken him to one side and said: look it would be easier to grant compassionate release if Megrahi dropped his appeal.
Q. So it is hearsay?
A. MacAskill has since fallen back on the fact there was a minute of the meeting and it reflects what went on. It's a load of waffle. If you look at it, it is one page long and a third of that page is a list of attendees. It's five bullet points, it is incredible. In any case, the whole point of taking someone aside is that it is not minuted.
Q. What do you make of MacAskill's denial that he said it would be easier to release Megrahi on compassionate grounds if he dropped his appeal.
A. It boils down to Obeidi's word against MacAskill and Obeidi's a Gaddafi regime relic and under house arrest. People will say Obeidi shouldn't be believed.
You have to look at motive. What was Obeidi's motive for lying to Megrahi. There was huge pressure to get him home and Obeidi maybe felt he could help persuade him. But beyond that, it is a bit opaque. Gaddafi wanted the conviction overturned, he wanted to get back into the international community and put the issue behind him. Then you look at MacAskill's motive and that [would be] to save the criminal justice system in Scotland a massive embarrassment.
They would be forced to account for why all the evidence the SCCRC turned up that had not been disclosed to the defence had been withheld. This would have been catastrophic for them, I think. Also, the real killers have gone free.
One of the real scandals in this is what resulted from the indictment that was issued against Megrahi and [his co-accused] Al-Amin Khalifah Fhimah 20 years ago. It should not be [MacAskill] that is on the hot seat, it should be the then Lord Advocate. Because he should have to answer to why there was non-disclosure of all the evidence.
But unfortunately what happens is that we get Kenny McAskill having to yet again make comments on the release of Megrahi. Until the government distances itself from the Crown Office on this and says, yes, we need to get to the bottom of it and order an inquiry - this is a scandal that will undermine the government. And MacAskill in that respect is in the firing line.
Q. Why does Megrahi not restart his appeal against conviction if he is innocent?
A. He's dying. He can't do those sort of things. Getting through a day is difficult enough. He's had 10 years away from his family. He would feel, yes, great if [he could clear his] name in future but he has too much on his plate. He could have started it before but the climate wasn't right for it. Nobody wanted an appeal before but now I think for the Scottish Government, an appeal might be the least worse option. Now, I know it is not within their gift to give it, but everyone is so up against the wall now, I think, that it will be more damaging to refuse any application made to appeal than to grant it.
I think his family may want to [orchestrate an appeal], but they are managing his death. They have the rest of their lives to do it. It is quite clear he won't be cleared while he's alive. His daughter is a lawyer and if they don't Jim Swire will. [Swire, a supporter of Megrahi, is the father of 23-year-old Flora who died in the atrocity]. It would require an application to the SCCRC and that has to pass two tests.
One, is there a potential miscarriage of justice, the answer to that is clearly yes because they have already said that. Secondly, which is trickier, is whether it is in the interests of justice. Then the circumstances of the abandonment of his appeal is important, because you have to demonstrate that by doing that he was not admitting guilt. Clearly he wasn't, but I think that's a hurdle he has to get over.
Q. So Megrahi wants a posthumous appeal?
A. He definitely wants to clear his name. We have not discussed the mechanism for a posthumous appeal but you can take it as read that he would want it.
Q. What does Megrahi think of Jim Swire's leading role in campaigning for him?
A. He's very touched and has massive respect for him.
Q. Has Megrahi provided information for any future appeal?
A. He's given it to the SCCRC already. They have interviewed him at length, they have access to all his precognition statements, they have everything they could need.
Q. How did Megrahi feel when Gadaffi paid compensation for Lockerbie, effectively admitting Libyan guilt?
A. He wasn't happy. The Libyan Government position was clear. They had to accept legal responsibility because otherwise they couldn't get rid of the sanctions in place at the time.
Q. So he would say Libya weren't responsible.
A. Oh yeah.
Q. When First Minister Alex Salmond says he is irritated and frustrated by the book's claims, how do you react?
A. I share the frustration that the attention has been on the issue of Megrahi's release, when it should be on the Crown Office's failure to disclose evidence. Hopefully, the government are coming round to being genuinely welcoming of the possibility of publication (of the SCCRC report). If that's the case then they must know a lot of the flak will come the way of the Crown Office.
Q. What do you want to see happen now?
A. First, a full inquiry which will cover why all the evidence was withheld from the trial. But I would also echo the relatives' call for a broader inquiry into Lockerbie, including the warnings that were given of an attack on Pan Am and why those weren't heeded. Secondly, the case should go back to the court of appeal. The case is still open and the police are going to Libya.
Q. If Megrahi is innocent, how did he get caught up in the biggest murder trial in history?
A. That's a very good question. You enter into the realms of speculation. It looks like it was a frame up, to put the blame on Libya. Not by the police. The police reasonably honestly followed the leads that were put their way.
Q. How did he feel in Tripoli airport when the Saltire was flown by Libyans – knowing as he must that this would injure the government which freed him?A. It was presented as a Government-orchestrated carnival. But if you read Wikileaks, a confidential cable from the US embassy undermined the US and UK government's claim that Megrahi's reception when he returned home was a grossly orchestrated pageant. It acknowledged that the crowd assembled at the airport numbered only around 100 and that only one Libyan TV channel broadcast the event.