It happened at around 1.50am on the slip road towards the Ivy Hill Hotel coming northbound on the A12 at junction 14 Margaretting. A white Vauxhall Mokka car was in collision with the crash barrier on the slip road. The driver of the car, a 30-year-old man from South Croydon, suffered life threatening injuries and was taken to the Royal London Hospital by ambulance.
A 17-year-old girl, a passenger in the car, suffered slight injuries.
Officers are investigating the circumstances of the collision and would like to speak to anyone who may have seen the crash or have seen the vehicle being driven prior to it.
Anybody that can help is asked to contact Pc Matthew Turner at Stanway Roads Policing Unit on Essex Police 101 or email email@example.com