Stunned firefighters found a cannabis factory in a semi-detached home in the Black Country after being called to tackle a house blaze.

Dodgy electrics rigged up at the property in Low Hill, Wolverhampton, to cultivate the plants sparked the outbreak – which sent flames shooting through the roof. Fire crews found hundreds of scorched plants and the roof well-alight after being alerted to the fire in Showell Road at around 8.30am yesterday. Police are now investigating the matter.

The garage of the suburban house had been lined with foil to aid the growing of the illegal enterprise and five van-loads of plants were taken away by police as residents looked on.

Shocked neighbours had to be woken from their beds by crews for their own safety.

Archie Weldon, spokesman for West Midlands Fire Service, said that the blaze totally destroyed the roof and loft.

“Frequently we find that the people who cultivate on this scale illegally wire these houses, bypassing meters and the systems that would normally make the use of electricity safe,” he said.

“Ultimately there has been some form of overheat which has caused this fire.”

One neighbour, who asked not to be named, said: “It’s a bit of a shock. We’ve never really seen anyone coming or going from there.”

Engineers from E.On were called in to make the electricity supply safe.

More than 300 cannabis factories were raided by police in the West Midlands last year. Complex lighting and growing equipment is often used and electricity is stolen from other properties by re-wiring. Suspicions are often raised when electricity firms notice huge power bills being run up by houses.

Gangsters have been known to booby-trap doors with electric circuits to hamper police or intruders.

Police smashed a cannabis factory network last year and found thousands of plants at homes in Owen Road, Merridale; Renton Road, Oxley; Beverley Crescent, Lanesfield; Farrington Road, Ettingshall Park, and two homes in Wynchcombe Avenue, based in Penn.