A motorcyclist has been hospitalised with serious injuries following a crash involving two lorries two motorcycles and a car.
Motorists are being advised to avoid the clockwise M25 following the collision near junction 27 with the M11 which occurred shortly before 12.30pm.
Southbound M25 traffic has been diverted on to the northbound M11 to Harlow Junction 7 to return on the southbound M11 to rejoin the M25.
Motorists have also been urged to avoid Junction 7 of the M11 until the diversions are lifted
The Highways agency estimates the carriageway to be cleared at around 7pm.
Police and ambulance crews attended and no other injuries and no arrests have been reported.