Officers were called at around 6.35pm on Sunday, 23 January, to a car in collision with a pedestrian on Gravel Hill in Croydon.
The pedestrian, a 40-year-old man, was taken by the London Ambulance Service to a south London hospital. His condition is described as critical.
The driver of the car – a Volvo V40 – stopped at the scene. The driver was not arrested and is assisting the police.
Detectives from the Roads and Transport Policing Command are investigating.
Any witnesses are asked to call police on 101 quoting reference CAD 5240/23Jan.
