The incident happened in Carshalton High Street near Ruskin Road at around 2.35am today (October 13).
Officers and London Ambulance Service crews attended and found a man injured.
He was taken to hospital for treatment where his condition is unknown at this stage.
Pictures, obtained by Your Local Guardian, show multiple cordons in place outside a row of shops.
The closure is causing congestion to Ruskin Road and heavier traffic on Manor Road from Wallington.
We have contacted the Metropolitan Police for further information.
A spokesperson for London Ambulance Service said: “We were called at 2.35am today (13 October) to reports of a road traffic collision on High Street, Carshalton.
“We sent an ambulance crew to the scene and treated a man before taking him to a major trauma centre.”
