Jim Swire, the father of a women killed in the bombing, has also given his support and insisted that the world should stop “mulling over” Megrahi’s release.

Scottish Justice Secretary Kenny MacAskill has been under intense pressure following the release of Abdelbaset Ali Mohmed al-Megrahi on compassionate grounds.

But today a Scottish Government spokesman confirmed it had received a letter from the former South African president expressing his support for the move.

In June 2002 Mr Mandela visited Megrahi in Glasgow’s Barlinnie Prison.

In the letter to the Scottish Government Professor Jake Gerwel, the chairperson the Mandela Foundation, said: “Mr Mandela sincerely appreciates the decision to release Mr al-Megrahi on compassionate grounds.”

It added: “Mr Mandela played a central role in facilitating the handover of Mr al-Megrahi and his fellow accused to the United Nations in order for them to stand trial under Scottish law in the Netherlands.

“His interest and involvement continued after the trial after visiting Mr al-Megrahi in prison.

“The decision to release him now, and allow him to return to Libya, is one which is therefore in line with his wishes.”

Scottish First Minister Alex Salmond said there “huge support” internationally for the decision to free Megrahi - who has terminal prostate cancer - to allow him to return home to Libya to die.

Mr Salmond told BBC News 24: “We have seen today that Nelson Mandela has come out firmly in support, not just as the towering figure of humanitarian concern across the world in the last generation, but of course somebody who brokered the agreement that led to the Lockerbie trial in the first place.”

He added: “Many people believe that you will achieve more in this world through acts of mercy than you will through acts of retribution.”

Jim Swire called on on the authorities in Scotland to “take responsibility” for reviewing Abdelbaset Ali Mohmed al-Megrahi’s conviction.

Dr Swire, whose daughter Flora was one of the 270 people killed when Pan Am 103 exploded over Lockerbie in December 1988, believes Megrahi is innocent.

And he has repeatedly called for a full inquiry into what happened.

In a letter to the media, Dr Swire said he was “delighted” that Megrahi, who has terminal cancer, had been freed on compassionate grounds.

Dr Swire, who attended Megrahi’s trial at Camp Zeist in the Netherlands, urged: “Let us stop mulling over the why and wherefore of Megrahi’s release.

“I for one am delighted that a man I now consider innocent because of the evidence I was allowed to hear at Zeist is at home with his family at last.”

Shortly before he was freed from prison on compassionate grounds, Megrahi dropped his second appeal against his conviction for the bombing.

But Dr Swire pointed out it was the Scottish Criminal Cases Review Commission (SCCRC) that had granted the right for that second appeal, stating Megrahi “may have suffered a miscarriage of justice”.

And he said: “More than 20 years later, we, the relatives, are still denied a full inquiry into the real issues for us - who was behind the bombing? How was it carried out?”

He urged “Let there be a responsible replacement immediately for the appeal a dying man understandably abandoned to ensure his release.

“Scotland should now take responsibility for reviewing a verdict which her own SCCRC already distrusts.”

Dr Swire continued: “The public’s knowledge of the shifty dealings surrounding the prisoner transfer agreement should help to swell demand for objective assessment of the Megrahi case.

“Overturning the verdict would open the way for a proper international inquiry into why Lockerbie was allowed to happen, who was really behind it, as well as how the verdict came to be reached.

“Let us turn our attention now, please, at last to the question of why we the relatives have been denied our rights to know who really murdered their families, and why those precious lives were not protected.”

Megrahi yesterday backed calls for a public inquiry into the atrocity, arguing it was “unfair” to the victims’ families not to have such a hearing.

The 57-year-old, speaking from a bed in his home in Tripoli, Libya, told The Herald newspaper: “I support the issue of a public inquiry if it can be agreed.

“In my view, it is unfair to the victims’ families that this has not been heard. It would help them to know the truth. The truth never dies. If the UK guaranteed it, I would be very supportive.”