A total of 23 windows were smashed, aluminium cowl was removed from the chimney and slats and felt from sections of the roof at Fakenham College.

The repair bill is expected to hit £3,000 to £4,000 and comes on top of a year where the cost of repeated vandalism at Wells Road college and linked Field Lane High School has run to more than £30,000, adding thousands to insurance premiums.

Facilities manager David Plummer said: "Initially I was quite cross but unfortunately I am getting more and more used to having to deal with this situation now.

"It is difficult to control. We have followed police advice, put in anti-climb paint, improved lighting, closed off areas, but we are a school not a prison.

"It is disheartening."

The latest attack took place between 6pm on Tuesday and 7.20am, Wednesday.

Police have collected DNA and forensics from the site.

Inspector John Bane, based at Fakenham, said: "This is pure wanton vandalism and we would urge anyone who spotted any suspiciously activity in the area or who believes they may know who is responsible to contact us immediately."

Anyone with information should contact PC Rebecca Rogers on 0845 456 4567 or Crimestoppers anonymously on 0800 555111.