Multiple lanes were closed on the M25 as emergency services dealt with a collision.
The incident was first reported at 07:06 GMT on the anticlockwise carrigeway between junction 17 for Rickmansworth and junction 16 for the M40, in Hertfordshire.
By 08:19 three of the four lanes were closed as ambulance and fire crews arrived, said National Highways.
An injured person was treated at the scene as vehicles involved were recovered.
