Detectives are appealing for witnesses following a fatal collision in Harmondsworth.
Police were called at 13:47hrs on Saturday, 3 March, to reports of a car in collision with a pedestrian on the westbound Colnbrook By-Pass a short distance before the junction with Stanwell Moor Road.
Officers, London Ambulance Service and a vehicle from London's Air Ambulance attended. The pedestrian, a man aged in his 80s, was pronounced dead at the scene.
While officers believe they know the identity of the man, enquiries are underway to identity and inform any next of kin. Formal identification will take place in due course.
The male driver of the car stopped at the scene. He has not been arrested.
Detectives are appealing for anyone who witnessed the collision to contact the collision investigation unit at Alperton on 020 8991 9555.