A fire broke out in an old changing room adjoining Challney High School for Boys on the evening of Wednesday 26 November.
The fire was allegedly caused by intruders in the disused building, with the alarm going off at 6.50pm.
Beds Fire and Rescue Service was called, and the incident was brought under control shortly after 7.30pm.
A spokesman for the school said: “The fire caused some damage to the electrical cabling and lighting in the unused rooms but did not reach the property of Challney High School for Boys.”