Detectives are appealing for witnesses and information following a serious collision in Waltham Forest.
Police were called at approximately 22:50hrs on Friday, 1 November to a collision between a car and motorcycle on Lea Bridge Road at the junction with Northumberland Road, E10.
Officers and the London Ambulance Service attended.
The 31-year-old rider was taken to an east London hospital with serious injuries. He remains in a critical condition.
The driver of the car stopped at the scene.
Detectives from the Roads and Transport Policing Command are investigating. They would like speak with anyone who witnessed the collision or who captured it on dash cam.
Anyone with information should call the Serious Collision Investigation Unit based in Chadwell Heath on 020 8597 4874 or via 101 quoting reference Cad 9432/01Nov.
There have been no arrests and enquiries continue.