Someone from outside a school's grounds fired BB pellets in a 10-minute attack, breaking windows and damaging cars, it has been claimed. 

An email sent to parents by Adam Palmer, interim executive head teacher at St Michael's Catholic School, which has been seen by the Bucks Free Press, says it happened at the High Wycombe secondary site just before lunch. 

The email said: "Prior to lucnh, we had an incident where an individual from outside the school boundary started to fire BB pellets into our school staff car park on the High Wycombe Secondary site. 

"In doing so, they managed to hit and break a window in our canteen and cause some damage to cars. 

"These pellets continued to be fired for around ten minutes before ceasing." 

At the time, pupils had just finished a lesson changeover and the "handful" of pupils and staff who were in the the area were quickly moved into the safety of the buildings. 

The email continued: "The police were immediately called and they advised us to move pupils into classes for their own safety. 

"The small number of pupils and staff in the areas near the car park where windows were at risk were immediately moved to safe areas." 

As a precaution, pupils were kept away from the school lane and car park areas with extra staff out on duty over lunchtime. 

Mr Palmer added: "We are aware that messaging and social media will lead to distorted versions of events which is why as soon as we have been able to, we have communicated the facts as they stand." 

He said the safety and welfare of the school community was their "first priority" during the "unfortunate" incident and they will continue to work with police. 

The school and Thames Valley Police have both been contacted.