The prosecution relied on a new law; the defendants claimed that supporting a share price with a guarantee was an unusual but longstanding market practice.
This information was passed on to the DTI corporate inspectorate in London, leading to an investigation in which Saunders' other secret share price support arrangements were unveiled.
The common factor in this case was that the alleged crimes were committed by businessmen who were outside the banking world but who had extensive financial connections to the City of London.
The guilty verdicts were upheld, though his sentence was halved after medical evidence was produced at the Court of Appeal that suggested he was suffering from serious illness.
Alzheimer's is an incurable, progressive degenerative disease of the brain, but Saunders subsequently made a full recovery from his medical condition.
Dr Patrick Gallway, a forensic pathologist who was an expert witness at the appeal, explained in 1996 that a diagnosis for the condition is initially "very difficult" and said "so we did not make one; we expressed worries about it.
It clarified that the biggest buyer of Guinness shares to support the bid was J Rothschild- part of the rothchild family.
The Report's inspectors said that the firm's motive was to create a favourable climate for obtaining future business from Guinness's City advisers, the stockbrokers Cazenove and the merchant bank Morgan Grenfell.
Bank Leu, still reeling from its role in a massive insider trading scandal in the United States, was ultimately forced to merge with Crédit Suisse in 1990.
Having had their sentences reduced on appeal, the "Guinness One" trial defendants also tried to reverse their convictions by using the 1997 DTI report and the UK Human Rights Act 1998.
In 2000 the European Court of Human Rights ruled that the 1990 trial had been unfair because there had been improper collusion between the DTI inspectors and the prosecuting authorities.