Traffic officers are appealing for witnesses after a car and cyclist collided on Saturday morning (July 12).
Police were called at about 5.30am and found a black Nissan Juke had been in an accident with a cyclist in Church Road, Northolt , opposite the junction with Eskdale Avenue.
The cyclist, a 30-year-old woman, was taken to a central London hospital with a head injury. Her condition is described as serious but stable.
The driver, a woman of about 30, and her female passenger, stopped at the scene and were taken to a west London hospital as a precaution.
There has been no arrest yet and enquiries continue.
Any witnesses or anyone with information is being asked to call the witness line on 020 8991 9555.