A motorcyclist has been taken to hospital in a critical condition after colliding with a van.
The incident happened at about 4.20am at the junction of Quicks Road in Wimbledon this morning.
A spokesman for the London Ambulance Service said: "We were called at 4.17am this morning to reports of a road traffic collision involving a motrosyclist and a van.
"We sent two ambulance crews to the scene.
Our staff treated a 41 year old male who was taken as a priority to St George's major trauma centre."
The driver of the van stopped at the scene and no arrests have been made.
Haydons Road has been closed in both directions between Merton High Street and Queens Road which is causing delays through the area.