Detectives are appealing for witnesses and information following a collision in Bromley.
Police were called at approximately 16:50hrs on 31 December 2018 to reports of a car in collision with a motorcycle on Grosvenor Road at the junction with Elysian Avenue in Petts Wood.
Officers and the London Ambulance Service attended.
The 27-year-old rider was taken to a south London hospital where he remains in a critical but stable condition.
The driver of the car stopped at the scene. There have been no arrests.
Detectives from the Roads and Transport Policing Command are investigating. They would like to speak with anyone who witnessed the collision.
Anyone with information is asked to contact the Serious Collision Investigation Unit at Catford on 020 8285 1574 or police via 101 quoting reference 4671/31Dec