Police investigating a shocking incident at a High Wycombe school have revealed more details about what happened. 

Yesterday afternoon, teachers and pupils at St Michael's Catholic secondary school in Daws Hill Lane were forced to move to safety after someone from outside the school boundary started shooting towards the staff car park. 

An email sent to parents by Adam Palmer, interim executive head teacher at the school, said the firing incident lasted around 10 minutes and caused damage to the canteen window and some cars. 

It was initially suspected that the weapon was a BB gun, but in an update from Thames Valley Police this morning, they believe ball bearing pellets were being fired from a catapult. 

They are urging any witnesses to come forward if they saw anything suspicious. 

A Thames Valley Police spokesman told the Bucks Free Press: "We are appealing for witnesses following an incident of criminal damage whereby a person fired ball bearing pellets at vehicles at a school in Daws Hill Lane, High Wycombe.

"The ball bearings are believed to have been fired from a catapult.

"There were no injuries but three cars were slightly damaged and a window at the school was also slightly damaged."

No arrests have been made, and anyone with any information is urged to call 101 quoting reference number 43210182104. 

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