The M25 has been shut due to a serious collision.
The motorway is closed clockwise between j25 for Enfield (A10) and j27 for the M11, according to Highways England.
Traffic was held temporarily anticlockwise between junction 26 and 25 to allow an air ambulance to land.
Essex Police is in attendance along with other members of the emergency services.
Police say one person has been taken to hospital but their injuries are not believed to be life threatening or life changing.
A 34-year-old woman from London was arrested on suspicion of drink driving.
There are currently long delays clockwise on the M25 from just after junction 24 for Potters Bar to junction 25, while there is also trapped traffic between junctions 25 and 26.
Anticlockwise, there are queues between junctions 27 and 26.
Traffic is held on both carriageways at this time as an air ambulance is on scene https://t.co/YX8fRd2k0A
— Highways England (@HighwaysEAST) November 11, 2020
Highways England is asking clockwise drivers to follow the hollow triangle symbol.
This diversion involves leaving the M25 at junction 25, taking the A10 down to the A406 North Circular, taking the A406 eastbound towards the M11, and then exiting the M11 where it meets the M25 at junction 27.
Delays can be expected on the A10 and A406 as well as in Woodridden Hill, Epping Forest, Dowding Way in Waltham Abbey, and in and around Waltham Cross, Cheshunt, and Potters Bar, as drivers seek alternative routes.
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