The M25 is closed clockwise between Junction 29 (Romford) and Junction 30 (Thurrock) due to a collision.
A lorry has collided with the safety barrier and caught fire.
The road is expected to remain closed for several hours.
There are long delays in excess of 30 minutes on approach to the closure with approximately 7 miles of slow moving traffic, with additional delays on the diversion route and other local roads in the area. Avoid area where possible.
Official diversion in place. Follow the route marked out with hollow triangle symbols on local road signs.
A spokesman for Essex Fre and Reasue said: Crews have extinguished a fire involving a lorry and its load of granulated coal on the M25.
Firefighters were called to the clockwise side of the motorway, just before Junction 30 (A13), and found an articulated lorry completely alight.
The lorry had shed its load, about 20 tons of granulated coal, of which about 10% was also alight.
Crews extinguished the fire by 1.50pm and left the scene in the care of the police and Highways England.
The road is likely to be closed for most of the afternoon for clean-up and recovery.
Essex Police say: A number of drivers were seen and recorded filming the scene of the lorry RTC and fire on the M25 today with their mobile phones. These drivers will be contacted in due course and will receive a fine and points. It is not acceptable and it is illegal