Detectives are appealing for witnesses following a traffic collision in northwest London.
Emergency services were called to the junction of Chichele Road and Melrose Avenue in Cricklewood on Thursday afternoon.
A motorcycle collided with a 39-year-old woman who was taken to hospital where she remains in a critical condition.
The motorcyclist was arrested at the scene, Met Police said, on suspicion of driving under the influence of drugs.
He was taken to hospital for treatment before being taken to a north London police station where he was subsequently released under investigation while enquiries continue, the Met said.
An investigation into the crash is ongoing. Detectives want to hear from anyone who saw the collision or captured it on dash cam or CCTV.
Anyone with information is asked to call the SCIU on 020 8246 9855 or via 101 quoting reference CAD 4799/07Jul.
