The crime ring was responsible for two-thirds of all the fake currency in circulation between 1993 and 1998, according to the police and the Bank of England.
Kenneth Mainstone, 61, and Anthony Wilkie, 59, were convicted by a jury at Winchester Crown Court for their part in the conspiracy. Three other members of the gang had earlier admitted their part in a plot that also involved counterfeit stamps and an attempt to produce pounds 1 coins.
The jury took more than 14 hours to convict the defendants on conspiracy, counterfeiting and forgery charges after a trial that lasted almost three months.
The fake English and Scottish pounds 20 and pounds 50 notes were of an extremely high quality and included a foil strip and a watermark of the Queen's head. One of the few flaws was that the words "Bank of England" at the top of each note were printed flat rather than raised.
The court was told that the fake notes were printed on a sophisticated four-colour printing press at Mainstone's home in Upminster, Essex. Mainstone, an "outwardly respectable" businessman who owned a printing company, worked with gang members Stephen Jory, 50, Bernard Farrier, 67, and Martin Watmough, 46, to produce vast amounts of counterfeit currency, which was distributed through underworld contacts.
A third man, Edward Burns, 67, who was said to have supplied paper for the production of the notes, was acquitted.
Wilkie, a toolmaker of High Wycombe, Buckinghamshire, supplied equipment for making perforations in fake stamps, a sideline to the gang's main operation. Wilkie and Farrier were also intending to mint fake pounds 1 coins, but the plan was thwarted when arrests began last summer following inquiries involving Hampshire police, the National Crime Squad, the National Criminal Intelligence Service and the City of London force.
Sheets of fake pounds 20 and pounds 50 notes were seized at Farrier's home in the Isle of Wight in August 1998. The police inquiry, called Operation Mermaid, then led detectives to Mainstone and Wilkie who were arrested and charged.
The money was linked with an earlier pounds 1.5m batch of fake cash for which Stephen Jory, an author of the book Super Grass, had been arrested in December 1994. He was caught by police in Enfield, north London, in August last year, handing over pounds 720,000 in fake notes to Martin Watmough.
Jory, of Barnet, north London, and Farrier, an engineer of Cowes, admitted conspiracy to counterfeit currency notes with intent. Police believe Jory used criminal contacts to distribute the money.
Farrier admitted a further charge of conspiring to counterfeit protected coins with intent, while Watmough, of Chingford, north-east London, admitted possessing counterfeit notes with intent. Mainstone and Wilkie denied the charges against them, claiming they played no part in the gang.
A Hampshire police spokeswoman said: "The result was the break-up of one of the most successful counterfeit rings ever to operate in Britain."
Mainstone and Wilkie were remanded in custody until 19 January, when they will be sentenced alongside Jory, Farrier and Watmough.Reuse content