A man responsible for making 14million fake £1 coins is starting a five-year jail sentence.
Police said the coin-making operation was one of the biggest they had ever seen.
Marcus Glindon, 37, ran the counterfeiting scam from a workshop on an industrial estate after losing his job as an engineer.
Despite the scale of the forging operation - which earned Glindon £300,000 - police said his lifestyle showed no "signs of wealth".
Officers who searched his workshop in Enfield, North London, discovered enough machinery for the large-scale manufacture of fake coins. There were also copies of the dyes used to imprint legitimate £1 coins.
Detectives arrested Glindon, from nearby Edmonton, and he admitted he had been producing the fake money for seven years.
The father of two said that he had worked alone for most of that time, under the orders of two men he knew only as "Tom" and "John".
They would deliver materials to his workshop, which he would use to produce both completed and blank coins.
Over the seven-year period Glindon produced a total of 14million coins, of which 2.5million were stamped and ready to spend. The coins have not been recovered.
Glindon estimated that at one stage he was making 12,000 pound coins a day. The finished items would be passed to his accomplices, who paid him around £2,000 in cash each week.
He said he believed the blank coins were taken away to another unit for finishing but claimed to have no knowledge of where this was located.
Royal Mint officials confirmed it would be extremely difficult for the general public to differentiate these counterfeits from genuine coins.
The fakes would also be accepted as genuine in some automated machines.
Dan Roberts, from the Metropolitan Police's Major Crimes Unit, said: "This was a sophisticated operation run over a seven-year period which flooded the economy with counterfeit pound coins.
"We have disrupted a nationwide criminal network and put a substantial dent into the illegal production of £1 coins."
Mr Roberts said Glindon was relieved when he was caught, saying he felt pressured into continuing the scam from the two men who "set him up in business".
He said: "He is a skilled engineer by trade. He was made redundant and was able to use his skills in this scam.
"He had felt under pressure from the two men. There were no specific threats - he felt he owed them to carry on."
Mr Roberts added: "He is quite a simple man, who was married and has two children. He was quite happy just to have a job. He was getting paid a wage and doing what he likes doing."
Glindon was jailed at Wood Green Crown Court on Wednesday after pleading guilty to conspiracy to produce counterfeit coins and other related offences.
Mr Roberts said police were still looking for the others involved in the operation.
"We've stopped their main source of blank coins," he said. "But we think there is another plant somewhere. The operation could be nationwide.
