ARSONISTS started a fire at the former Gilberts Hill School in Old Town.

Smoke was seen pouring from the boarded up first floor windows at the derelict Dixon Street building.

Police today warned there could be further incidents at the school, which is due to be turned into flats, until it is made secure.

Witnesses saw a group of between 10 and 15 children running down a fire escape from the first floor shortly before the fire began and police have confirmed they believe the youngsters were responsible.

Mark Gaskarth of Swindon Fire Brigade said: "We believe the fire was started deliberately and we have spoken to the police.

"A lot of our fire appliances were tied up in the early stages of this fire and if there was a serious call in Swindon it would have been delayed.

"This fire put crews in danger and other people in danger."

Firefighters wearing breathing apparatus entered the building to extinguish the blaze, which was started in a large sink in the corner of the building yesterday afternoon.

The brigade used industrial fans to clear the smoke from the building, and four fire engines, two from Swindon and one each from Westlea and Stratton, were called to the fire.

The building suffered serious smoke damage throughout but fire damage was limited because there was no furniture to burn.

WPC Tracy Doughty of Swindon Police said: "We know this fire was started by a group of children who were seen exiting the building shortly before smoke was seen.

"We are concerned about the building because once one thing happens it opens the floodgates.

"We believe it is due to be developed so we are hoping to get the premises totally secured in order to stop anything else happening."

The school closed in July 2000 after a 15 month battle by parents and governors to save it was lost in February that year.

Since then it has lain derelict but in March this year developers Bower Mapson were given permission to build 10 flats at the site, with work due to begin this summer.

Witnesses to the fire are asked to contact WPC Tracy Doughty of Swindon Police on Swindon 528144.