Detectives are appealing for information and witnesses following a fatal collision in Barkingside.
Police were called at 07:23 hours on Thursday, 3 November to reports of a collision between a car and a motorcycle on the A12 eastbound at Ley Street junction with Horns Road.
Officers, the London Ambulance Service, London Fire Brigade and London's Air Ambulance found a male motorcyclist, in his 40s seriously injured. He was taken to an east London hospital where he died at 09:37hrs.
Next of kin have been informed.
Formal identification awaits and a post-mortem examination will be scheduled in due course.
The car stopped at the scene and the driver, a male in his 40s was arrested on suspicion of death by dangerous driving. He is currently in custody at an east London police station.
Road closures are currently in place.
Detectives from the Serious Collision Investigation Unit are investigating.
Anyone who witnessed the collision or has any information is asked to contact the Serious Collision Investigation Unit on 101 or Crimestoppers anonymously on 0800-555-111.