At approximately 7.30pm on Friday, 27 November police were called to reports of a collision involving a pedestrian and a car on Great West Road, at the junction with Heston Road, TW5.
A 29-year-old man was seriously injured – he was taken to hospital where he remains in a critical condition.
Police are making enquiries to contact and inform next of kin.
No arrests have been made and enquiries are ongoing.
Officers from the Serious Collision Investigation Unit ask any witnesses, or those with dash cam footage, to call 020 8543 5157, or 101 ref CAD 6305/27Nov20.