THE blaze that gutted an empty industrial building on the Isis trading estate was the second deliberately lit fire of the night.

Firefighters attended the incident at the Bamptons building in Stratton Road after the alarm was raised at about 11.30pm on Wednesday.

It was a return visit, as they had been there just hours earlier after a report of a minor blaze in nearby building.

Wiltshire Fire Brigade's incident commander Andrew Hargreaves said that the second blaze, in the former Bampton's building, was well alight when they arrived.

Bamptons was a specialist vehicle body workshop which started in 1932 and closed in 2003. It also built caravans.

He said the main priority had been to stop the flames spreading to surrounding, occupied buildings.

At its peak, 35 firefighters from four stations tackled the blaze using six pump trucks and a hydraulic crane, as well as setting up a mobile command post.

Mr Hargreaves said that concerns about the strength of the building led firefighters to decide it was not safe to enter it and had instead to tackle it from outside.

They were able to bring it under control in 25 minutes but had to spent another two and a half hours at the scene, making sure it was fully extinguished. "In an unoccupied building at that time of night, we are pretty sure it was deliberately lit and told the police that," Mr Hargreaves said.

He said the blaze showed the risk of fires started deliberately posed to neighbouring businesses.

"That is why we are so keen to drive down the incidences of deliberately lit fires," he said.

"It was quite a significant fire. We were concerned about the structure of the building. It wasn't possible to go in to the building."

Resident John Killingback said that he heard the fire brigade arrive about 8pm. He said they returned about 11.30pm, when he raced outside to capture the fire on his mobile phone camera.

Mr Killingback said he heard what he thought were fireworks going off and raced outside to see what was happening.

The fire was popping and crackling.

"The fire brigade were hacking off the hoardings to get the hoses in," he said.

"They were there for quite a while."

Swindon police said that they were treating the two fires as arson, and believe the same people were responsible for both.

They are appealing for information about the incidents.

"Fortunately, the derelict building was empty at the time of the fire which is believed to have been started deliberately," a police spokeswoman said.

"The ferocity of the fire has rendered the building beyond repair.

"We are appealing for witnesses or anyone with information to come forward."

Anyone with information should phone PC Dave Flynn at Swindon Police on 0845 408 7000 or Crimestoppers on 0800 555111.