Ian ClarkeFirefighters faced a tough task tackling a blaze in a derelict building in Dereham after arsonists started a bonfire on its first floor.Two crews from Dereham and one from Watton spent more than an hour and a half at Malthouse Cottages, off Norwich Road, on Tuesday.Ian Clarke

Firefighters faced a tough task tackling a blaze in a derelict building in Dereham after arsonists started a bonfire on its first floor.

Two crews from Dereham and one from Watton spent more than an hour and a half at Malthouse Cottages, off Norwich Road, on Tuesday.

They were called at about 4.25pm but access was difficult to the boarded-up building and they had to cut a hole in the roof for ventilation.

The bonfire had burnt through the upstairs floor and the flames spread downstairs.

The building is known to be used for drinking and drug taking and there have been previous fires there.