Officials declined to give more details, but it was understood two people were on board when it crashed at the Valley Royal Air Force base.

"We are aware of an incident today at RAF Valley involving a Hawk aircraft," a Ministry of Defence spokesman said.

"We are investigating the incident and it would be inappropriate to comment further at this stage."

Police confirmed they attended the scene.

At RAF Valley on the island of Anglesey, wreckage from the jet could be seen close to the runway.

The Red Arrows, Hawk fast jets flown by experienced military pilots, are known around the world for their daring stunts.

They are based at RAF Scampton in Lincolnshire, eastern England.