An 18-year-old man has been arrested on suspicion of arson after a house fire that led to the discovery of a suspected cannabis factory hidden in the attic.

The fire broke out at a terraced house in Dudley Street, off Dick Lane, Tyersal, Bradford, at around 4am yesterday. The blaze is thought to have started in the loft, the contents of which were destroyed.

The man arrested in connection with the incident was later released on bail.

Bradford fire station crew commander Jamie Collins said the roof joists and other items in the loft had been burning.

He said: “Most of the damage is to the roof, so the roof will probably need replacing. It’s burnt through a lot of the roof joists supporting the tiles, and we had to strip part of the roof away.”

He said no adjoining properties had been affected, and no one had been hurt. Late yesterday, West Yorkshire Fire and Rescue Service said the cause of the fire remained under investigation, but issued a general warning about the dangers associated with cannabis farms.

“High powered lamps can create a strong heat source,” a spokesman from the fire service said.

“The lamp can drop down and catch fire to anything combustible below.”

The fire service also explained that, if an electrical meter had been bypassed, this posed an extra danger to the fire crew. Where electricity has been bypassed there can be a lot of individual circuit ring mains which are still live and this creates the potential for harm to firefighters.” Since April 2009, firefighters in West Yorkshire have attended 38 incidents involving cannabis farms, 33 of which were fires.

Martin Speed, District Commander for the fire service for the Bradford area, said: “Fires involving cannabis farms can present a major hazard to the public and our firefighters.

“Tampering with electrical supplies poses a great risk of electrocution and the potential for devastating fires.”

Ofgem, the office of Gas and Electricity Markets, said the estimated amount of electricity theft was £200m nationwide, which added £7.70 to an energy bill per home.

Around a third of the electricity theft volume was used to power cannabis farms. Ofgem is due to publish new supply licence obligations to strength the arrangements for tackling electricity theft.