The M1 northbound carriageway has now been reopened after emergency services attended to a two-vehicle crash this morning.
Police, fire and ambulance crews rushed to the scene between junction 6a for Watford and the M25 and junction 7 for Hemel Hempstead, where a black BMW and black Ford Focus collided shortly before 10am.
The M25 slip road was also blocked as Highways Agency officers assist with the clearing of the road.
‘Trapped’ traffic was being let through in two lanes but all lanes have now been fully opened.
It is thought a road barrier was also damaged in the accident.
The East of England Ambulance Service sent one vehicle to the scene after reports a man had suffered back injuries.
He was initially thought to be trapped in his vehicle but is now thought to have been removed safely, without the need for firefighters to cut open the car.
He is likely to be conveyed to hospital, though it is not yet known which one, and his injuries are not thought to be life-threatening.
The incident is causing tailbacks further south.
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