The jury has not yet agreed a verdict on a remaining charge accusing Kevin Cressey of possessing over 50 kilos of cannabis resin with intent to supply.
Cressey, 38, from Ditton, Kent, had offered or given Detective Constable John Donald, 37, thousands of pounds in return for police information on undercover operations.
One such operation involved Kenneth Noye, whom Kent police currently wish to question in connection with the M25 "road rage" murder of 21-year- old Stephen Cameron.
Noye, 42, was a key figure in the pounds 26m Brink's-Mat gold robbery case in 1983. He was cleared of murdering undercover policeman John Fordham who was investigating the raid but was later sentenced to 14 years for handling some of the bullion.
Cressey had denied all charges against him - claiming he had not been drug dealing but had wanted to expose the corrupt officer. But the prosecution alleged that Cressey hoped to escape a lengthy jail sentence after he was arrested for drugs dealing.
Donald, a Metropolitan police officer serving with the South East Regional Crime Squad (Sercs) at Surbiton in 1993, has admitted his part in the corruption.
Cressey was targeted in 1992 for surveillance by the Sercs as a suspected drugs dealer.
Donald was part of their special drugs investigation unit and was "one of the most experienced and knowledgeable officers on the team," said John Nutting, prosecuting in Cressey's trial. But he was also "steeped in corruption and dishonest to the core".
Cressey went to the BBC Panorama programme to expose the detective and Donald was trapped after subsequent meetings between the pair were filmed and taped, the court heard.Reuse content