An M25 crash has left evening commuters facing gridlock this afternoon, with the anti-clockwise carriageway near Merstham seeing “very heavy” traffic and cars left stationary in queues.
The incident happened on the anti-clockwise carriageway before Junction 7 for the M23 and was first reported at 3.49pm on Wednesday.
This is a developing story. We will update this article as more information becomes available.
What happened
- Where: M25 anti-clockwise, before Junction 7 (M23 interchange), near Merstham
- When: First reported at 3.49pm on Wednesday, October 14
- Impact: Very heavy traffic; photos show stationary queues
Evening rush hour chaos
Photos taken on the M25 show the extent of the disruption, with cars stationary and queueing back from the scene.
The timing could hardly be worse. The M25 is at its busiest during the evening rush hour, and an incident on the anti-clockwise carriageway — the route used by drivers heading from Kent and the Dartford Crossing towards Surrey and the M23 — ripples out quickly.
Wednesday evenings are consistently among the worst times for M25 congestion. Midweek traffic volumes peak as commuters, freight and leisure travel overlap, and the network has minimal spare capacity to absorb an incident.
Junction 7 is one of the M25’s key interchanges, connecting the orbital motorway with the M23 towards Gatwick and Brighton. Any disruption here affects not just M25 traffic but drivers heading to and from the airport.
What drivers should do
Drivers heading anti-clockwise towards Junction 7 should expect significant delays and consider alternative routes where possible.
National Highways advises checking live traffic conditions before setting off, allowing extra journey time, and never driving through red X signals or using closed lanes.
If you’re caught in the queue, stay in your vehicle with your hazard lights on if traffic is stationary for an extended period, and keep the emergency services’ access route clear.
The M25’s rush-hour problem
The M25 is one of the busiest motorways in Europe, carrying around 200,000 vehicles a day on its western sections. Even a minor incident during peak hours can cause delays stretching for miles.
The stretch around Junction 7 is particularly sensitive. It sits at the meeting point of M25 orbital traffic, M23 traffic to and from Gatwick, and local Surrey traffic — a combination that leaves little slack when something goes wrong.
This is the second M25 incident affecting London drivers today, following disruption earlier in the day.
What happens next
Emergency services and National Highways traffic officers will work to clear the scene and reopen lanes. Once the vehicles involved are recovered, traffic typically takes time to clear as the backlog works through.
Drivers should check National Highways’ live traffic updates for the latest on lane closures and expected clearance times.
For those heading to Gatwick Airport this evening, the disruption is a particular concern. The M23 is the primary route to the airport from London, and delays on the M25 feed directly into airport-bound traffic. Travellers with evening flights should allow significantly more time than usual.
The RAC advises that in stop-start motorway traffic, drivers should keep a safe distance from the vehicle in front, avoid unnecessary lane changes, and switch off engines if stationary for long periods to save fuel and reduce emissions.
Motorway crashes during peak hours are a recurring problem on the M25. National Highways data consistently shows that the evening peak sees the highest incident rates, as high traffic volumes leave little margin for error. Even minor collisions can close lanes for an hour or more while vehicles are recovered and debris is cleared.
We will update this story as more details emerge.
London Streets has been covering the Thameslink disruption and the Wellesley Road crash in Croydon.
