An Irish republican leader is responsible for flooding the UK money markets with near-perfect counterfeit money, it has been claimed.
The BBC's Panorama programme has traced the supply of millions of fake US dollars to Sean Garland, a leader of the former paramilitary group, the Official IRA.
Panorama also reveals that the profit from passing the currency is used to fund the republican group - which split with the better known Provisional IRA in 1970.
The fake currency - known to intelligence agents as
"superdollars" because it is so realistic - is believed to be printed in North Korea.
It finds its way into the UK via the Russian mafia, with Sean Garland - who has contacts in Russia and North Korea - acting as the alleged ringleader of the UK distribution.
The operation in the UK was smashed after a police investigation which resulted in several people being sent to prison. However, police believe the ringleader got away.
He was never arrested or questioned in connection with the plot, although his name was mentioned in court and he is known to US intelligence agencies as someone involved in the passing of superdollars.
The money had been passing unnoticed in banks throughout the UK, until a massive undercover police operation in 2000 called Operation Mali.
The police investigation showed a detailed picture of an international counterfeiting cartel run by a tightly-knit group of criminals.
They discovered the group was getting superdollars in Moscow, before the counterfeit cash was smuggled to Dublin.
From the Republic of Ireland, it was then taken to Birmingham and distributed in the criminal underworld.
Panorama has also learned that for several years, authorities in Washington have believed Sean Garland to be a major player in the international superdollar distribution network.
Bill Gertz, the national security correspondent for the Washington Times, is aware of his activities.
He told the programme: "I first heard the name Sean Garland when it was referred to me in a classified intelligence report as certainly someone who had been involved [in a counterfeiting plot].
"A top secret document says Sean Garland is suspected of being involved with counterfeiting US currency."
Panorama can also reveal that two of the men jailed in the multi-million pound counterfeiting case had regular contact with Mr Garland in Moscow.
Police evidence from the trial reveals that on 25 June 1999, Terence Silcock - who has been jailed for six years for his part in the operation - flew into Moscow to close a counterfeit deal.
Panorama obtained flight manifests, which detail passenger lists into the city on that day. They show that on the same day Silcock arrived in Moscow, Sean Garland did as well.
Mr Garland was being followed by an elite team of Russian police.
Vladimir Uskov followed Sean Garland in Moscow
General Vladimir Uskov and his men tracked him as he visited the North Korean Embassy in Moscow.
He said: "Our information was that people working there may have been involved in the transportation of counterfeit dollars."
The programme also claims that despite their best attempts to not be seen together, Panorama has obtained copies of phone bills which prove that the Birmingham criminals called Sean Garland while in Moscow.
The claim is also backed up further with signed statements from several members of the Official IRA who confirm that Garland was involved in the spreading of counterfeit money in the UK and Ireland.
Panorama: The superdollar plot will be broadcast on BBC One on Sunday at 2215 BST