The appearance of the convicted Lockerbie bomber on Libyan television has confirmed that a "great mistake" was made in releasing him from jail, Foreign Secretary William Hague said today.
Mr Hague said Abdelbaset al-Megrahi's release from a Scottish prison almost two years ago on compassionate grounds was "absolutely the wrong thing to do".
In footage seen by the BBC last night, a television presenter introduced Megrahi at what appeared to be a pro-government rally, and said his conviction was the result of a "conspiracy".
Megrahi served nearly eight years of a 27-year sentence after being convicted of killing 270 people in the bombing of Pan Am Flight 103 four days before Christmas in 1988.
He returned to Libya in August 2009 after being diagnosed with advanced prostate cancer. The Scottish Government accepted advice that he had about three months to live.
At a press conference in central London, Mr Hague said the footage demonstrated that this advice was "pretty much worthless".
He said: "I think the appearance of Mr al-Megrahi on our television screens is a further reminder that a great mistake was made when he was released.
"The Prime Minister and I, when we were in opposition, both strongly disagreed with that position by Scottish ministers.
"We disagreed with what has subsequently been revealed about the facilitation by the previous Labour government at Westminster of moves towards the release of al-Megrahi."
He added: "This was absolutely the wrong thing to do. It shows the medical advice it was based on was pretty much worthless and I think many people, particularly the families of those killed at Lockerbie, I think their anger and outrage at this release will be further intensified by what we have seen.
"So it has always been our view this was a mistake and this simply confirms that."
Of the 270 victims of the disaster, 189 were American. Eleven residents of Lockerbie, in Dumfries and Galloway, also died after the plane crashed down on their homes.
A Scottish Government spokesman said they were satisfied that Holyrood's Justice Committee has "examined all relevant aspects" of Megrahi's release.
However, the same committee will shortly decide whether to call for a public inquiry into his conviction.
Committee convener Christine Grahame has said it is time for "a clean, clear look at the role of Scottish justice" because of the number of "conspiracy theories" surrounding the conviction.
The issue was referred back to Holyrood thanks to a long-running Justice For Megrahi campaign, led by Dr Jim Swire whose daughter Flora died in the bombing.
The campaign supported the decision to release Megrahi and wants an independent inquiry into his conviction. This call has been rejected by the Scottish Government.
A Scottish Government spokesman said: "Al Megrahi is dying of terminal prostate cancer and was released on compassionate grounds based on the recommendations of the Parole Board, the prison governor and the medical report of the Scottish Prison Service's most senior health professional.
"The decisions to reject the prisoner transfer application and grant compassionate release were taken by the Justice Secretary according to the precepts of Scots law. Our sole interest was taking a justice decision based on Scots law without fear or favour, which was exactly what was done.
"This material is all in the public domain, including the medical report, and it all vindicates the Scottish Government's position. Indeed, it is clear that only the Scottish Government played with a straight bat on this matter, while the UK Government said one thing in public and another in private.
"The Scottish Parliament Justice Committee examined all relevant aspects of this issue (Megrahi's release) and concluded that the decision was taken in good faith.
The spokesman continued: "Instead of criticising a senior health professional, Mr Hague should understand that the medical advice to the Justice Secretary came from Dr Andrew Fraser, director of health and care of the Scottish Prison Service.
"Dr Fraser is a professional of impeccable integrity and he concluded that his clinical assessment was that a three-month prognosis was a reasonable estimate, drawing on the work of a range of specialists and other Scottish health service professionals involved in Al Megrahi's care from when he was first diagnosed with cancer in 2008.
"Given the importance of this case, it was appropriate that the most senior health professional in the SPS was responsible for providing the medical report. With the exception of this point, ie the most senior SPS health professional providing the report, this is exactly the same process that has been followed in the more than 60 cases considered under the relevant legislation passed in 1993."
Professor Roger Kirby, a leading prostate surgeon and founder of The Prostate Centre, said: "It was always foolhardy to put a three-month prognosis on his survival, because advances in treatment, such as new chemotherapy and immunotherapy techniques that he is likely to be receiving, could keep him alive for a while yet, maybe even several more years.
"What used to be a hopeless situation for patients at advanced stages of prostate cancer is now more favourable. The silver lining to this story is that other patients with similarly advanced disease should not give up hope and should ask their doctor about the possibility of having these new treatments."