Nineteen police forces across England and Wales raided suspected indoor cannabis factories in Operation Keymer, a coordinated crackdown running from 25 September to 5 October 2006.[1][2] The Association of Chief Police Officers said criminal gangs saw home growing as low-risk and high-profit, with 200 plants turning over about £30,000 in three months, and warned of fire and electrocution risks from electricity supplies the growers bypassed.[1] Police asked the public to watch for covered windows, visits at odd hours, gardening equipment left outside and the pungent smell of growing cannabis.[1]

Officers closed factories, arrested suspects and moved against criminal profits under the Proceeds of Crime Act.[1][2] Announcing the results, police said fifteen forces had destroyed 28,000 cannabis plants and 54 kilograms of prepared cannabis worth more than £2.5 million, arrested 133 people including one wanted for murder, and seized £160,000 in cash together with four houses, five cars and antiques.[3]