Stretches of the M25 in Essex and the M26 in Kent have been closed due to two separate incidents.
Emergency services were dealing with a collision involving a pedestrian between junctions 29 and 28 on the M25.
In an unrelated incident, Kent Fire and Rescue Service were called to a blaze between junctions five and two of the M25, resulting in the closure of the nearby M26 eastbound.
National Highways said the M25 in Essex was closed anti-clockwise between J29 for Hornchurch and J28 for the A12, near Brentwood after a serious collision, thought to have happened around midday.
The closure was causing delays of about an hour and 20 minutes and traffic jams stretched back around five miles, the experts said.
Essex Police and other emergency crews rushed to the area, and traffic officers were there to manage vehicle flows.
Traffic was queuing back towards J30 with Lakeside Shopping Centre and the A13, and to J27 with the M11.
Drivers were being advised to follow diversion symbols.
In Kent, a lorry fire forced the closure of the M26 eastbound between the M25 J5 for Chipstead and J2A near Wrotham Heath.
Traffic was backed up for about seven miles, causing delays of about 55 minutes.
“Once the fire has been extinguished, the carriageway will require debris to be cleared and the road surface to be inspected,” National Highways warned.
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