Detectives are appealing for witnesses to a serious collision in Ealing.
Police were called to reports of a collision between a car and a pedestrian on Gunnersbury Avenue, Ealing at around 13:42 on Tuesday, 2 October.
Officers, London Ambulance Service and London's Air Ambulance all attended the scene.
The pedestrian - a 60-year-old woman - was taken to hospital where she remains in a life-threatening condition.
The car – a blue Vauxhall Astra – stopped at the scene. There has been no arrest.
Detectives from the Serious Collision Investigation Unit based at Alperton are investigating.
Any witnesses are asked to call them on 020 8991 9555.