Police are appealing for witnesses and any drivers who may have dashcam footage following a serious collision in Streatham.
Officers were called at approximately 21:00hrs on Thursday, 25 June to reports of a collision involving a car and cyclist on Streatham Hill, at the junction with Telford Avenue.
A silver VW Tiguan travelling towards Streatham South was involved in a collision with a cyclist.
The 37-year-old cyclist was taken by the London Ambulance Service to a south London hospital where she remains in a critical condition. Her family has been informed.
The driver of the VW Tiguan, a woman aged in her 30s, stopped at the scene and was arrested on suspicion of driving offences. She remains in custody at a south London police station.
Officers from the Roads and Transport Policing Command are investigating.
They are particularly keen to hear from any motorists who were on Streatham Hill at approximately 21:00hrs and who may have recorded the events leading up to the collision on dashcam.
Any witnesses yet to speak with police are asked to call the Serious Collision Investigation at Catford on 020 8285 1574 quoting reference Cad 8825/25Jun.