Four-vehicle crash blocks M25 near Watford
A four-vehicle collision has blocked the anti-clockwise M25 motorway close to Junction 20 (A41 interchange) near Watford, resulting in delays of up to an hour.
Traffic and delays
The M25 is closed at Junction 20, with traffic diverted via the exit and entry slip roads to exit and rejoin at the junction. National Highways reported delays of approximately 50 minutes as of 8:30 pm, with congestion reaching around three miles and delays of 30 minutes on approach.
Earlier at 8 pm, the congestion was estimated to stretch back about five miles, possibly reaching the M1 motorway.
On-site response
Herts Police and the East of England Ambulance Service are attending the scene. A police spokesperson stated:
“We are currently dealing with a high volume of traffic on the M25 anticlockwise at Junction 20 (Watford/Kings Langley) following a road traffic collision. We would ask you to please avoid the area at this time.”
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Social media update
The @HighwaysEAST Twitter account posted:
“The #M25 anti-clockwise is closed within J20 near #Watford due to a 4 vehicle collision.@roadpoliceBCH + an Ambulance are on scene. Traffic is diverted via the exit/entry slip roads, to leave/rejoin at J20. Delays of 30 minutes on the approach, 3 miles of congestion.”
Posted November 9, 2025
Author’s summary: The multi-vehicle crash near Watford has caused severe traffic disruption on the M25, with police urging motorists to avoid the area while emergency services manage the scene.