It is not just bad behaviour by pupils which damages schools, as teachers in Leicestershire have discovered to their cost.
The county has spent more than pound;250,000 in the last year installing CCTV cameras and security fences at schools to tackle an epidemic of vandalism.
Around 300 crimes have been carried out in the past year, mostly by youths living in the area or by ex-pupils rather than existing students. Premises vandalised ranged from inner-city comprehensives to village schools.
The Old Mill primary in the village of Broughton Astley had plants, pots and troughs destroyed in a recent attack, which left the playground littered with broken glass and soil.
Castle Rock high school in Coalville lost its gym in an arson blaze, while nearby Warren Hills primary has installed CCTV and perimeter fences to fend off the vandals.
Mount Grace high in Hinckley has been hit by several night-time incidents in which intruders left alcohol bottles in its playground.
The school is now spending pound;40,000 on CCTV and fences. John Thomas, headteacher, said: "We've already got four security cameras, but we're getting four more."
New College in Leicester has been forced to install a tall fence around its buildings and an intercom system on its gate.
David Kershaw, executive principal, said the measures were needed because non-students had been entering the grounds and riding around on motorbikes.