Two women have been arrested on suspicion of dangerous driving following a collision during a police pursuit in Croydon.
The BMW crashed into another car after driving away from a marked police unit on routine patrol on Kent Gate Way in Addington on Monday night.
The 39-year-old man driving that car was taken to hospital with potentially life-changing injuries.
The two female occupants of the BMW car were taken to hospital to be treated for minor injuries.
The Met Police said: "A crime scene is in place at Gravel Hill and the road is currently closed.
"As is routine in these incidents, the Directorate of Professional Standards and Independent Office for Police Conduct have been notified."
Two fire engines and one fire rescue unit were called to the scene at 11.55pm.
A spokesperson for the London Fire Brigade said: "Two cars were in collision. One man was released from a vehicle by police officers before the brigade arrived and was taken to hospital."