A 55-year-old woman was left fighting for life following a collision with a lorry in Vauxhall.
Emergency services scrambled to reports of a serious incident on Wandsworth Road, opposite Vauxhall Bus Garage at around 1pm on Monday.
The woman was rushed to a south London hospital where she remains in a critical condition.
The driver stopped at the scene and is assisting police, Scotland Yard said in a statement.
Pictures shared on social media showed a number of vehicles from London Fire Brigade, London Ambulance Service and Met Police in attendance.
A spokesman for the Metropolitan Police said: "Police were called at 12.59pm on Monday, August 20 to reports of a collision involving a pedestrian and lorry on Wandsworth Road, opposite Vauxhall Bus Garage.
"The pedestrian, a 55-year-old woman was taken to a south London hospital where she remains in a critical condition.
"Detectives from the Roads and Transport Policing Command are investigating.
"They would like to speak with anyone who saw the collision occur, or who may have dash cam or mobile phone footage."
London's Air Ambulance said: “Our advanced trauma team was dispatched via aircraft by London Ambulance Service at 1.06pm today to reports of a road traffic collision on Wandsworth Road.
"After treatment on scene the patient was transferred by road to a major trauma hospital accompanied by London’s Air Ambulance.”
Firefighters also attended to support emergency services.
Anyone with information is asked to contact the Serious Collisions Investigation Unit on 020 8285 1574.
