Two elderly people have been taken to hospital after the car they were travelling in crashed on the M25 near St Albans.
The green Ford Mondeo crashed into the central reservation between Junction 22 and Junction 22 clockwise at about 1.35pm.
One of the passengers had chest pains and the other had neck and back pains.
They were both taken to Watford General Hospital by ambulance.
The fast lane of the motorway is still closed and officers from Hertfordshire Constabulary remain at the scene.