A huge fire which ripped through a derelict building in Gainsborough is being investigated as an arson attack.
Firecrews were called to the blaze on the top floor of the three storey building on North Marsh Road in the early hours of last Wednesday (January 11)
Lincolnshire Fire and Rescue Service sent four pumps and a cherry picker to the incident which was reported at 4.57am.
Crews used two main jets to extinguish the blaze.
Overnight, the fire service advised people to stay away from the area if possible until the fire had been brought under control.
A Lincolnshire Police spokesman said there was no one in the building at the time.
Police are treating the incident as a case of deliberate ignition and are appealing for witnesses.
The building is the former Chesley Learning Centre, a school for children outside mainstream education, which has been empty since it closed five years ago.
Jo Noble, headteacher of Gainsborough Nursery School which is near to the building, said it had become a target for vandals
She said: “It was in a dilapidated state already and a lot of the windows are out and not boarded up.
“As it is now about a third of the roof is burnt away.
“Our caretaker called me at 5.45am on Wednesday to say she couldn’t get into school as the fire fighters were still dowsing it down.
The road was closed at both ends and opened up again just before eight, so it didn’t affect parents.
She added: “It was the far side of the building from us which caught fire, so the nursery was not in any danger.
“If it had been the other wing it could have been a different matter.”
It is understood developers have planning permission to demolish the building and build flats on the site.
She added: “A couple of months ago we had to call the police as people were throwing things from inside of the building through the windows and into the street.”
Anyone with information should call Lincolnshire Police on 101 or by contacting Crimestoppers anonymously on 0800 555 111 or online at www.crimestoppers-uk.org, incident number 38 of 11.