Even the police recognised his craftmanship. Counterfeiter Thomas McAnea's £20 bills were among the best ever seen, indistinguishable to the untrained eye from the real thing.

"There is a touch of the geek about him," said the detective who eventually brought him to justice, Graeme Pearson, director general of the Scottish Crime and Drug Enforcement Agency (SCDEA). "He sees the challenge of producing banknotes as a thrill in itself."

The underworld appreciated McAnea's skills even more. They called him "Hologram Tam", celebrating his greatest talent, to add the holograms and watermarks to counterfeit cash.

Yesterday McAnea, 58, was sentenced to six years and four months in jail for his part in a major forgery operation that police believe could have destabilised the entire British economy. Five of his associates were also jailed, for between 15 months and four years. Their mistake? The holograms that gave McAnea his nickname.

Last year the Serious and Organised Crime Agency (Soca), England's version of the SCDEA, came across £3m worth of Bank of Scotland £20 notes. They looked odd. They didn't have their watermarks or holograms. The money, Soca operatives realised, was on its way to be finished by a master. The bills were Scottish. Did SCDEA have any clues? They did: McAnea's past.

A decade ago Hologram Tam, and his sidekick John McGregor, walked out of jail on a technicality. McAnea had been sentenced to 10 years for a counterfeit operation out of a print shop in Glasgow. The pair were released, however, on appeal thanks to the perfect irony: detectives had made a printing error on the search warrant for his premises.

So when SCDEA learned there were Bank of Scotland twenties on the go, they knew where to look.

McAnea, explained Mr Pearson, would be on your list of top 10 counterfeiters. "And there wouldn't be 10 on it," he added. Cue Operation Fender, one of Britain's biggest ever anti-forgery police operations.

For four months SCDEA officers staked out McAnea's business, Print Link (Scotland) in St George's Cross. As officers watched members of well-known crime syndicates come and go, they realised McAnea was printing more than just menus for local Chinese and Indian takeaways.

On January 28 of this year, SCDEA pounced. They found McGregor, 49, in the middle of printing a batch of £20s. He was counting out half a million of them on the floor. The shop was equipped to make far, far more, up to a £1m in a single shift.

Astonishingly, the little printshop had the ability to churn out £1bn a year in fake cash, although it is not thought the operation was working at full capacity. McAnea and McGregor clearly hadn't forgotten their first brush with the law. In the printshop was a picture of the judge who first sent them down, with the words "He's the man" daubed over him.

"This group knew what they were about," said Mr Pearson yesterday. "I would describe them as a thieves' kitchen. Counterfeiting isn't a victimless crime. It often affects the poorest and most vulnerable in society.

"People think it is a wheeze, like in the old black and white films. But what we have here are people who are doing it to order to enable criminal gangs to make profit."

McAnea, however, didn't seem to make a killing. A former print union official, his life had long fallen apart and his lifestyle was modest. He couldn't, after all, joked detectives, pay himself in his own fake cash. He had to pass it on to much more nasty people.

McAnea's defence advocate, Peter Hammond, suggested his client had little choice but to work for criminal gangs.

"He was asked to do a favour for people. Initially he refused but he was put under a degree of pressure and that became what he interpreted as veiled threats to himself and his family. The court yesterday heard McAnea was promised payment, but never got any.

So how much cash did McAnea put out there?

Police believe they nipped his operation in the bud. Aside from £496,200 found in Print Link, police later seized 406,000. Another £672,880 with McAnea's serial numbers have been recovered in the UK banking system.

Lord Bracadale, sentencing, said confidence in currency was essential and the Glasgow operation had undermined that. "It is likely to lead to loss being sustained by innocent people who find themselves in possession of these notes, only to discover they are worthless," he added.

Football fans were among such potential victims. McAnea were understood to have intended to flush fake euros on to the continent every time Scotland or one of the Old Firm teams played in Europe.

After all, McAnea and McGregor had originally been caught after trying to flood England with fake Scots twenties during Euro 96.

McGregor; Robert Fulton, 63; and Steven Todd, 24; all of Glasgow, were each sentenced to four years for their part in the operation.

Joseph McKnight, 57, of Glasgow, got three years; and Rodney Cadogan, 39, of London, got 15 months.

Maria Campbell, 39, of Old Kilpatrick, was sentenced to 150 hours community service after pleading guilty to producing false documents.