Police discovered a massive cannabis farm worth up to £1million in a raid yesterday. Officers raided the home and found four rooms filled with over 250 cannabis plants.The raid took place in Tolworth Rise North, near Kingston upon Thames, south west London, at 11.20am yesterday.A Kingston police spokesman estimated the plants were worth £1m in total.Officers found hundreds of plants surrounded by lighting and cables. Despite the haul, police are yet to make any arrests and have appealed for witnesses to come forward.