A driver has been seriously injured in a collision involving a racing car.
Cambridgeshire Police said they were called to Duxford Airfield, home of the Duxford Imperial War Museum, at 9.26am to reports of a crash between a Formula One-style car and a lorry.
The female driver of the car is believed to have suffered serious injuries.
Gary Sanderson, spokesman for the East of England Ambulance Service, said paramedics were at the scene.
It is thought the car was taking part in testing at the time.