Two people were treated by the London Ambulance Service at the scene before being taken to hospital, one of which taken by air ambulance. One of them had a chest and leg injury.
A London Ambulance Service spokesperson said: “We were called at 8.33am today (29 October) to reports of a road traffic collision on the M25, Waltham Cross. We sent an ambulance crew and an incident response officer to the scene.
“We treated two people and took one patient to hospital as a priority. The other patient was taken to hospital by East Anglian Air Ambulance.”