Two safes cemented into the floor of a Kingston lock-up and stuffed with £1.2m of cash were seized in police raids.
Officers also discovered two money-counting machines in Sutton and over 50 kilos of skunk cannabis in a property in Ashtead as part of the 35 places they raided yesterday.
Police believe the illegal industry made approximately £1m a week by importing cannabis from Holland, hidden in wholesale flower deliveries.
DI Steve Wilkinson, Special Intelligence Section, said: "We believe that these criminals have been operating a highly sophisticated operation, hidden behind the guise of a legitimate flower wholesaler.
"We have worked closely with the other law enforcement agencies, through Europol, and the success of these raids has smashed this drugs ring, putting them permanently out of business."
Previous police activity, by the Met's Special Intelligence Section, targeting the gang, has resulted in the seizure of approximately 1,000 kilos of skunk cannabis.
Officers arrested 13 men and one woman in the morning raids and took them to an unidentified south London police station.
Homes in Worcester Park, Epsom, East Molesey, Ashtead, Ewell, Surbiton, Kingston, Wimbledon and Sutton were among the addresses raided.
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