Arsonists are suspected of torching a three-bedroomed Victorian house in Kennington which drug dealers once planned to use as a cannabis factory.

Fire crews were called to 153 Kennington Road in the early hours yesterday after flames were seen coming from the roof of the detached house, which has been empty since July.

Twenty firefighters from stations in and around Oxford were called to the scene at 3.30am.

They left at 5.30am after controlling the fire, but were forced to return at 8.30am after a blaze started again in the roof. Smoke could be seen billowing 30ft in to the air from acoss the village.

Retired teacher Mark Forder, 61, who lives next door with his wife Jennifer, said: "A couple of passing railway engineers knocked on our door after spotting the fire about 3.40am.

"The fire brigade left last night assuming it was out, but it started up again this morning.

"The house was being used by tenants, but it has been empty since last July. We were told the police visited the house at that time and found no-one there, but they discovered the place was being prepared as a cannabis factory."

Another resident, who asked not be named, said: "It's a real shame because this was a nice family house."

Incident commander Richard Bowley, from Oxfordshire Fire and Rescue Service, confirmed that 20 firefighters were forced to return to Kennington Road when the fire re-ignited at 8.30am - officers are checking to see if the second blaze was also started deliberately.

Mr Bowley said: "The fire spread rapidly through this detached vacant property because of the way it was constructed. It has a timber roof, timber ceilings and floors.

"There was no immediate danger to neighbouring properties but officers will be damping down the building for several hours to make sure the fire is properly out."

Mr Bowley added that initial investigations suggested the blaze had been started deliberately and that the fire service was working with Thames Valley Police on an inquiry.

Anna Huggins, from Thames Valley Police, said: "We can confirm that the fire at the house in Kennington Road is being treated as arson."

She added that officers were called to the property in July after receiving intelligence that the property was being prepared for use as a cannabis factory.

Miss Huggins said: "We went to investigate and found a small amount of cannabis and equipment for growing cannabis. The property was vacant at the time and there have been no arrests."

Anyone with information about the arson is asked to call police on 08458 505505.