The M25 is completely closed and traffic is being diverted to the M4 due to a lorry catching fire between the exit and entry slip roads.
Bucks Fire and Rescue Service said no-one has been hurt.
Delays on the M25 anticlockwise has reached J16 of the M40. Clockwise is also slow approaching J15 due to onlookers.
The M4 is slow as people head to J4 and then turn around again at the Heathrow roundabout.
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Part of the M25 motorway in Surrey was closed because of flash flooding on Thursday.
The road has now reopened.
The M23 was also closed, but reopened on Thursday night too.
Illegal raves have been booming during lockdown, but their story goes back a long time.
A man has died after a the car he was driving collided with the central reservation on the M25.
It happened between junctions 28 and 27, near Theydon Bois in Essex, at about 20:10 BST on Tuesday.
The driver died at the scene and the road was closed.
Essex Police said that a passenger in the car suffered minor injuries and was taken to hospital as a precaution.
Anyone with information about the crash is asked to call the police on 101.
These aerial shots show how coronavirus has changed our public spaces during lockdown.
Highways England is warning drivers to make sure trailers are secure before setting off.
- Copyright: Highways England
Three lanes of the M25 in Surrey were closed after a car caught fire, Highways England said.
The car caught light between junctions eight for Reigate and nine for Leatherhead on the clockwise carriageway at about 09:00 BST.
Traffic was queuing back to junction seven for the M23.
The same stretch of road was closed for about nine hours on Thursday after an articulated lorry jackknifed near Leatherhead.
The clockwise carriageway was closed between junctions eight and 10 (Wisley) after the lorry crashed with a London cab and a Citroen at about 04:45 BST on Thursday.