Fat bundles of banknotes were left in a forgotten underground safe because of the runaway success of Britain's largest skunk cannabis smugglers.
Police were astonished when they uncovered the true scale of a drugs conspiracy taking place under the veil of a legitimate flower wholesaler.
In just two years the gang masterminded at least 88 shipments between Holland and Britain netting them up to £70 million in cash.
At its peak, the network was bringing in 551lb (250kg) of the highly potent cannabis strain into the country every week, enough for 225,000 street deals.
The flood of money left the directors of the London and Surrey-based crime gang with serious cashflow problems, but not the type experienced by most.
The drug smugglers were left cooking up schemes to launder huge quantities of dirty cash without alerting the authorities.
Up to £11 million was handed to a crooked employee at the World Currency Exchange, near London's Liverpool Street railway station.
No records of any transactions were kept, but police believe much of it was wired into accounts in Pakistan and Dubai.
Some of the money was also converted to 500-euro notes to be smuggled out of the country.
When Calais customs officers intercepted one car heading for Spain, they found £500,000 stuffed behind the dashboard.
The three gang directors, Terrence Bowler, 40, Peter Moran, 37, and Mark Kinnimont, 40, were family men who took care to enjoy superficially unremarkable lives.
They lived in comfortable homes in Kingston, Surbiton and Fulham, west London, and had a fleet of upmarket, but not flamboyant, vehicles.
The men travelled abroad to splash out, even heading to Geneva on one occasion to stock up on luxury watches, and sent their children to private schools.
Hundreds of thousands of pounds was used to buy land and fund a development of 12 luxury villas in Lanzarote.
But plenty of money was left lying about, including £60,000 ridden with mildew in a safe sunk into the floor of a lock-up in Deer Park Close, Kingston.
Detective Chief Inspector Steve Wallace, of Scotland Yard's special intelligence section, said the gang "cornered the market" for skunk in England.
He said: "They were making grotesque profits on the back of the misery this drug causes. They were involved in a trade that allowed them to enjoy lavish lifestyles.
"So much cash was generated by the venture that during our searches we found cash rotting away. In the floor of one premises was a safe containing £225,000, of which £60,000 was going mouldy.
"There was so much cash lying around that they did not know what to do with it. We took the ruined money to the Bank of England as it was no good to anybody."
Police swooped on the gang in November 2008 after more than two years of painstaking detective work, including months of undercover surveillance.
The conspiracy operated under the cover of a flower business, T&K Flowers, based in Chatham, Kent.
Boxes of flowers were used to conceal heat-sealed 2.2lb (1kg) packages of skunk cannabis, sold for £3,400 each.
The gang switched their original route through Harwich in Essex when a £750,000 consignment was intercepted by Customs in July 2008.
The operation refocused on Hull, with a new warehouse in Leeds employed as a base to repackage and re-label the drugs for customers.
Lorries and vans were then used to ferry the drugs to lock-up garages in Worcester Park, Kingston, Epsom and Ashtead.
Most customers bought between 44lb (20kg) and 110lb (50kg) of cannabis per deal, with rudimentary records kept in a notebook.
Mr Wallace said the top trio of directors never came into contact with the drugs or large quantities of money.
The senior detective said they held meetings in restaurants and took anti-surveillance steps, including checking their cars for tracking devices.
He said: "These individuals were at the very top of these organised crime networks. They had good character and had never come to our attention before.
"These people are the untouchable ones. To all intents and purposes they appear to be respectable businessmen.
"It is only when you look into the detail of where all the money is coming from that you find out."
Police continue to hunt one suspected gang member - Anthony Mills, of Beckenham, south-east London, who has disappeared, possibly abroad.Reuse content