Essex Police have released CCTV images of five men they want to talk to in connection with a collision which left an officer seriously injured.
The officer was on a police motorbike on the M11 when it was involved in a collision with a black BMW at about 4pm yesterday.
The driver of the BMW failed to stop at the scene of the collision and made off towards Essex.
The vehicle, which had been stolen, was later found in Harston in Cambridgeshire
The police officer was taken to Addenbrooke's Hospital with serious leg injuries.
Anyone with any information should call DS Gaylor on 101 or Crimestoppers, anonymously, on 0800 555111.