Arson attacks on schools have risen dramatically in the last five years with 16 schools in Britain targeted each week, according to a new survey.

The Arson Prevention Bureau (APB) says the rise in the number of deliberate fires is costing more than �1m a week.

In West Yorkshire alone, there were 33 fires last year which were started while pupils were in class.

The APB said that in 2001 fires in schools started deliberately cost an estimated �56m, a rise of 30% in five years.

'Disruptive'

Its chief executive, Jane Milne, said: "The rise in daytime arson attacks on schools is very alarming and poses a very real and increasing risk to the safety of pupils.

"And in addition to safety, these attacks can cause severe disruption to pupils' education, impacting on the morale of the school and its pupils for many years."

The bureau, set up jointly by the Home Office and the insurance industry, believes that many more smaller fires, in bins for example, are going unreported.

This may seem minor but are often tell-tale signs of more serious arson attack to come, the bureau believes.

Police helicopters

There is often an upturn in arson and vandalism against schools during school holidays.

Last year Merseyside Police used helicopters in an attempt to cut down on such attacks during the summer holiday.

They patrolled schools which were be at risk of attack, using cameras and searchlights.

The cameras on the helicopters transmitted pictures back to a control room, which were then used to direct police on the ground towards suspects or suspicious activity.