Police were called by London Ambulance Service at 8.03pm on Thursday, 28 November to reports of a road traffic collision on the A3 at Coombe Lane, SW20.
Officers and London Ambulance Service [LAS] attended.
At the scene a vehicle had been in collision with a motorcycle. The motor cyclist was found at the scene suffering serious injuries.
He was taken by LAS to a west London hospital. We await an update on his condition.
The vehicle that collided with the motorcycle failed to stop at the scene.
A road closure is in place with all A3 lanes southbound closed to traffic.
Motorists are advised to use alternative routes.
No arrests. Enquiries continue.
Anyone who witnessed the collision or has dash cam footage is asked to call police on 101 quoting 7461/28NOV, Tweet @MetCC or call Crimestoppers anonymously on 0800 555 111