POLICE are hunting arsonists after a fire at a computer firm caused more than £250,000 worth of damage.

The fire is the second suspected arson attack in Cavalier Court, on Bumpers Farm, in just three weeks.

Now police are appealing for witnesses and warning companies on the industrial estate to tighten up security.

Firefighters were alerted at 12.25am on Sunday and four crews headed for the computer firm, Advanced Digital Technology.

The fire started in a wheelie bin pushed against a door, and the flames were already starting to spread into the building when the first crew arrived.

Firefighters, using two appliances from Chippenham and two from Corsham, were hampered in their efforts to tackle the blaze because the fire moved into a service cupboard with a live electrical and gas intake.

They had to carry out defensive firefighting until the gas and electricity board could turn off the supply which took around half an hour.

"If there is high voltage current we can't go in firing water around," said Station Officer Julian Parsons.

It took around four and a half hours to put out the fire, which caused severe damage to two rooms.

The crews had to tear away walls and floors to stop the fire spreading further into the building, which also suffered extensive smoke damage.

Managing director Phil Crook said he was extremely upset when he saw the extent of the devastation.

"I didn't realise it was a fire to start with. I was called out because the alarm went off. I saw the fire when I arrived. I was really disappointed and aggrieved to think someone could have done this."

The company, which supplies computer hardware and software, as well as providing maintenance and support, has operated for 20 years and employs 12 people.

Mr Crook was obliged to make hurried arrangements for his employees on Monday because his premises were unusable, and managed to find alternative offices elsewhere on the Bumpers Farm estate.

He said the 5,000 sq ft offices had sustained more than £250,000 damage and it will take a couple of months before the premises could be used again.

Three weeks ago another fire was started in a wheelie bin outside the offices of Linkspan Interiors Ltd in Cavalier Court.

The fire started a gas leak, which ignited under the exterior wall. Firefighters arrived to tackle the blaze before it caused an explosion.

Contract manager Jim Smiley said security is definitely now an issue and the company has taken preventative measures including a check on the storage of rubbish.

The building did not suffer damage to the same extent as Advanced Digital Technology and the 12 members of staff were able to return to work straight away.

But more external repair work is still needed on the building.

"I was very surprised on Monday to see another scorched building," said Mr Smiley.

"I expect it was a prank by youngsters. We have a security firm here and they are pretty good. But they can't be everywhere at the same time."

PC Ian Lansdown, of Wootton Bassett police, went to investigate the site on Sunday morning.

He said the police are treating the fires as deliberately caused.

"Whether they intended to set fire to the buildings is a different matter," he said. "My instincts tell me this was a prank that went badly wrong. The area is frequented by youths and no-one can suggest any motive for targeting these people."

He is appealing for witnesses, or anyone with information, to come forward.

"We have a number of lines of enquiry which we are following up," he said. "If there were people in the area we would like to speak to them."

Firefighters were advising Bumpers Farm businesses on Tuesday about fire safety.

PC Lansdown said they will be issued with crime prevention advice, including warnings not to leave rubbish in bins outside buildings.

Anyone with information can contact PC Lansdown on (01793) 856603.