A blaze which ripped through a derelict primary school is being treated as arson.
Firefighters spent eight hours tackling a large scale blaze at a former Greenland Primary School building in South Moor on Saturday evening.
The building, which had been empty for a number of years, was left significantly damaged by the flames.
Five fire appliances, an aerial ladder platform and an incident command support unit were dispatched to the scene of the blaze at 7pm and were joined by police officers and a Hazardous Area Response Team (HART) from the North East Ambulance Service.
Firefighters managed to get the fire under control by 3am before leaving the scene.
A joint police and fire investigation was launched and Durham Constabulary have revealed the fire is believed to have been started deliberately.
Crime scene investigators were spotted at the scene on Sunday as they probed the cause of the fire.
Crews used the aerial ladder platform to tackle the fire from above while firefighters also used jets at ground level.
Images show the extent of the damage sustained by the building with the roof almost completely destroyed.
Nobody was injured in the fire but firefighters urged members of the public to avoid the area.
Anyone with any information on the incident is asked to call Durham Constabulary on 101, quoting incident number 377 of June 8.
