The documents, which were never disclosed to defence lawyers working for Abdelbaset Ali Mohmed al Megrahi, also point to another potentially important eye witness whose evidence was never followed up by detectives.

Those revelations, published on Megrahi’s website, further undermine the credibility of Tony Gauci, the Crown’s main witness at Camp Zeist.

The Herald revealed two years ago that Gauci and his brother Paul had been paid millions of dollars by US justice officials, but the amount is 50% more than previously thought, and the direct involvement of the Scottish officers who brought Megrahi to trial had not been made public.

It will fuel fears of a miscarriage of justice, and strengthen calls for an independent inquiry into Lockerbie.

A four-year investigation by the Scottish Criminal Cases Review Commission (SCCRC) found a number of documents which had not been shown to the defence. The non-disclosure would have been a key plank of Megrahi’s appeal, which he abandoned shortly before his release from Greenock Prison in August.

Megrahi, who is now receiving treatment for prostate cancer in Tripoli, is instead using his website to make his case. Yesterday’s extracts include references to letters written by Scottish police to the US Department of Justice, applying for a reward on behalf of the Gauci brothers.

The papers reveal that Tony Gauci received more than $2m after the trial and Paul, who never testified at Camp Zeist but “exercised considerable control over his brother”, received more than $1m. The family previously had financial problems.

Megrahi’s website summary states: “Tony Gauci and Paul Gauci had both expressed an interest in financial reward prior to giving evidence at trial. None of the documents in which references to the brothers’ financial interest or to the FBI offers of reward was disclosed and no mention of this was made to the defence. Many of the references . . . were in diaries kept by police officers. Parts of the diaries were missing and, most unusually, no police notebooks were kept. Letters written by the Scottish police to the US Department of Justice applying for a reward on behalf of the Gauci brothers were also recovered.”

Another section suggests Megrahi might not have bought clothes later found next to the suitcase carrying the Lockerbie bomb. A new witness called David Wright claims to have seen other men buying them in Tony Gauci’s shop in Malta.

In November 1989, Mr Wright called Dumfries and Galloway Police to say he had been in Mr Gauci’s shop when two Libyans bought similar clothing. He said Mr Gauci referred to them as “Libyan pigs”. But his statement was never followed up by police.

A Crown Office spokeswoman said yesterday: “All of these issues could have been raised during the course of the appeal which Mr Megrahi abandoned.”