Valletta, Malta  - The Lockerbie bomber's request to drop the appeal he fought so hard to gain smacks of a political deal, a legal expert appointed by the United Nations to monitor the trial has told The Sunday Times of Malta.

Hans Koechler said oil interests and joint security considerations will prevent the truth of one of the worst terrorist acts of the 20th century from emerging.

The man convicted of the 1988 bombing of a Pan Am airliner over Lockerbie, Scotland, is likely to be released from prison on compassionate grounds, British media reported Wednesday.

Abdel Basset al-Megrahi, who is serving a 27-year prison sentence for the December 1988 bombing of the plane, which killed 270 people, is suffering from terminal prostate cancer. There are reports that he has requested to drop his appeal against conviction.

Al-Megrahi was convicted mainly as a result of the testimony of a Maltese shop owner who identified him as the man to whom he had sold the clothes in which the bomb was wrapped. Concerns were raised that the judgment was based on circumstantial evidence.

Koechler was handpicked by the then UN Secretary General Kofi Annan to monitor proceedings in the trial held in the Netherlands in 2000. He had concluded that a miscarriage of justice may have occurred. Several years on he stands by his conclusion.

Koechler told the Maltese newspaper that if the ongoing appeal is dropped, the truth may never come out and justice will never be done.

"Neither the UK nor the Scottish establishment is interested in the truth. The constellation of interests between the UK and Libya is such that both sides have decided to put the past behind and engage in a new phase of 'realpolitik'," he added.

Koechler's view is echoed by Robert Black, the Scottish legal expert who was the architect of the original trial in the Netherlands in 2001.

Black told The Sunday Times of Malta that the decision to drop the appeal smacked of an intergovernmental arrangement with which al-Megrahi believed he had no option but to comply.

Maltese lawyer Emmanuel Mallia, who had followed proceedings and examined evidence at the trial said: "I am sure there are local authorities who may have very important documents which, when revealed, may show that Malta had absolutely nothing to do with this unfortunate and tragic episode in history."

The prosecution said al-Megrahi had originally placed the bomb on an Air Malta flight, which was then transferred at Frankfurt airport to Pan Am flight 103A that later exploded over Lockerbie after leaving Heathrow.

The news of al-Megrahi's probable release was mixed - some British relatives of the victims believe the wrong man is behind bars while American families said the request for release was unacceptable. US Secretary of State Hillary Clinton joined senior US officials in pressing Scotland not to release the Libyan. (dpa)