Officers were called at approximately 8.15pm on Monday, 14 December to reports of a car in collision with a pedestrian in Morden Hall Road.
London Ambulance Service also attended the scene and the pedestrian, a woman believed aged in her 60s, was taken to hospital for treatment. She remains there in a critical condition – enquiries continue to locate and inform her next of kin.
The driver of the car stopped at the scene and is assisting police with enquiries – there have been no arrests.
Officers a keen to speak to anyone that was on board a route 118 bus that was stationary at a bus stop by Morden Lodge at the time of the collision and may have witnessed the collision.
They would also like to hear from any road users who may have captured the incident on dashcam footage.
Officers from the Serious Collision Investigation Unit based at Merton investigate.
Anyone who can assist police is asked to contact the witness appeal line on 020 8543 5157, call 101 and quote CAD6838/14Dec.