Managers of a Bradford firm say the company may be forced to relocate to Leeds, with the loss of 30 jobs, after being targeted by vandals.

Bosses of ASC Cartons Ltd claim vandalism has already cost them more than £5,000 in repairs, increased security measures and lost working hours.

Commercial manager Andrew Woodhead said an attack over the weekend saw the factory's glass roofing smashed, resulting in a morning's production lost on Monday as workmen cleaned up the mess.

"We've had problems over the years with children on the roof, but at the moment it's particularly bad," said Mr Woodhead.

"At the weekends you can see the children smashing things, it's getting out of control."

The business has been based at the site in Leeds Road for 12 years, but Mr Woodhead said it may be forced to move if the trouble does not stop.

"It's getting to the stage where we may have to re-locate," he said.

"We don't want to do that - we want to bring employment into the area. We are one of the last manufacturing companies in the area and we don't want to be forced out by the vandals.

"The police say they will come round and make a bit of a show, but there doesn't seem to be any stopping the situation."

A West Yorkshire Police spokesman said police are aware of the problems faced by the factory.

"It is being investigated, and the Problem Oriented Policing team has also been made aware and will be looking at the problem" he said.

"Obviously we take all reports of nuisance and vandalism seriously and ask anyone who sees anything suspicious or has any information relating to this incident to contact Shipley police on (01274) 537447."

Mr Woodhead said he believes the derelict Council houses which back on to the factory are making the problem worse, with children using roof tiles as ammunition to throw at the factory.

"The housing has got to be cleared up. It's just attracting children - if you give them tiles to throw then they will throw them," he said.

A Bradford Council spokes-man said the properties are due to be demolished within the next two months.

"We are aware of a problem with vandalism in the area and are concerned at the effect this is having on local businesses.

"We will, therefore, act quickly to demolish these properties," he said.