Detectives from the Serious Collision Investigation Unit are appealing for witnesses following a collision in Hounslow.
Officers were called at 09:05hrs on Monday, 5 August to Staines Road to reports of a van in collision with a pedestrian.
Police and the London Ambulance Service attended. The 88-year-old pedestrian, from Hounslow, was taken to a central London hospital for treatment; his condition is described as critical. His family has been informed.
The driver of the vehicle stopped at the scene.
No arrests have been made and enquiries continue.
Any witnesses or anyone with any information is asked to contact officers from the SCIU on 020 8543 5157 or contact via Twitter @MetCC. Please quote Cad 1896/05AUG.
To give information anonymously contact Crimestoppers on 0800 555 111 or online at crimestoppers-uk.org.