Three years ago, the bill for repairing broken windows at Eastbourne Comprehensive in Darlington was £17,000.

Only one set of toilets out of four was useable - because the others had been so badly vandalised.

But in 2003, the school was awarded a £240,000 Home Office grant to tackle the problem and the turnaround has been dramatic.

The school installed a high fence, lighting, closed-circuit television (CCTV) cameras at entrances and exits, and vulnerable areas were supervised. Teachers also worked to change the ethos of the school, and prevent vandalism from within.

Once labelled the most burgled premises in Middlesbrough, Newlands School is starting to win its war on vandals and thieves with the help of police.

Headteacher Steve Wing said: "This school is in a relatively isolated position on the edge of an estate.

"The single biggest problem for us is repairs to window and door frames - this ends up costing money which should be spent on children's education.

"Over the course of a year, repairing broken windows may run into a few thousand pounds."

At Christmas, the police installed security fences and cameras in the school and it has been very effective.

"The problem really is getting better," said Mr Wing. "Since then, we haven't had a single break-in or vandalism incident."

Schools are now built with security as a top priority. Alderman Leach Primary School, in Darlington, was targeted by vandals 38 times last year - leaving school bosses to dish out thousands of pounds in repairs. Out of desperation, the LEA hired a security guard.

But in February, the school moved into a multi-million pound building in a new community and the problems stopped.

Deputy headteacher Helen Steele said: "The old school was targeted severely and the bill for re-doing the windows was phenomenal, it ran to thousands. But since we moved to the new school, we have only had one incident and nothing was damaged."

Durham County Council has been improving school security since the early 1990s and has put in burglar alarms connected to police and CCTV cameras.

Council bosses have also encouraged schools to use SmartWater - a forensic solution with a DNA-style code, to mark property.

A spokesman for the council said: "Whatever the current cost of theft and vandalism may be, it still represents wasted money - money which could be spent employing additional staff, repairing buildings or providing equipment to support the curriculum."

At the end of last month, headteachers from schools across Darlington got together to learn more about SmartWater, which has reduced crime at some schools by up to 70 per cent.