More than 500 cannabis plants have been removed from a house in Oxford in the area's largest raid this year.
Thames Valley Police raided a house in Old Road, Headington, and found about 550 plants with a street value of £100,000 being grown in five rooms.
The electricity mains had been spliced to create a "dangerous set-up".
The raid was part of Operation Falcon, a project run by police, the city council, health and social services, and other support agencies.
Pc Charlie Ellis, who led the seizure operation, said: "There was a complex and sophisticated set up with the potential to produce cannabis worth tens of thousands of pounds.
"I would ask local residents to be vigilant because these cannabis houses are usually full of illegal wiring and electrical work, and are a very real fire hazard to neighbouring properties."