Massive Illegal Bitcoin Mine Discovered In UK At Suspected Cannabis Farm Massive Illegal Bitcoin Mine Discovered In UK At Suspected Cannabis Farm A raid by West Midlands Police uncovered the illicit operation at an industrial estate northwest of Birmingham, Britain's second city. The site housed around 100 computers and had bypassed electricity meters. London: Drugs police in central England spotted the tell-tale signs of a cannabis farm: visitors at all hours, extensive wiring, ventilation ducts and unusual amounts of heat being generated. But on closer inspection, they exposed another operation reliant on massive power usage: a cryptocurrency mine that was stealing electricity from the national grid.