Drivers on the M25 are facing long delays this evening after two lorries crashed near Iver Heath, closing three lanes of the motorway.
The collision happened on Wednesday afternoon, and emergency services were quickly on the scene. With three lanes shut, traffic has been squeezed through the remaining lane, causing queues to build in both directions around one of the busiest stretches of the orbital motorway.
Motorists have been warned to expect significant delays and to allow plenty of extra time for their journeys. National Highways is urging drivers to check conditions before setting off.
Delays building around Iver Heath
The M25 near Iver Heath sits on the western section of the motorway, between the M40 and M4 interchanges — a stretch that carries huge volumes of freight and commuter traffic every day. When lanes close here, the knock-on effects spread quickly across the network, with tailbacks often reaching back for several miles.
Drivers heading anti-clockwise towards Heathrow and the M4, and clockwise towards the M40 and Watford, are both likely to be affected while recovery and clear-up work continues.
Diversion routes and alternatives
Anyone who has not yet joined the M25 may want to consider alternative routes. Depending on your direction of travel, the A40 through Denham and Uxbridge, or the A412 and A4007 through the Colne Valley, can offer a way around the worst of the congestion — though these local roads are likely to be busier than usual as traffic diverts.
For longer journeys, the M40 to the north or the M4 to the south can serve as alternatives for parts of the route, but drivers should check live traffic information before committing to a diversion, as conditions change quickly during an incident like this.
Public transport may be a better bet for some journeys this evening — Chiltern Railways services run through nearby Denham and Gerrards Cross, and London Underground and Elizabeth line connections remain available for those heading into or across the capital.
Why the M25 seizes up so fast
The M25 is Britain’s busiest motorway, carrying around 200,000 vehicles a day on its western sections. With so little spare capacity, even a single-lane closure can trigger miles of queues — and a three-lane closure, as here, effectively reduces the motorway to a single file of traffic.
Lorry collisions are particularly disruptive because recovery takes longer: damaged HGVs often need specialist recovery vehicles, spilt fuel or debris must be cleared, and barrier or carriageway repairs may be required before lanes can safely reopen. It is not unusual for the effects of a serious HGV crash to last for several hours after the vehicles themselves have been moved.
This is the latest in a string of M25 incidents this week. Earlier today, an overturned caravan brought the motorway to a standstill near Staines, while a separate overturned car stopped all lanes near Thorpe. A lorry fire near Enfield also caused major disruption.
What to do if you are caught in the queues
If you are already stuck in the traffic, the advice is simple: stay in your vehicle, keep a safe distance from the vehicle in front, and do not attempt to use the hard shoulder unless directed to by police or traffic officers.
Keep an eye on overhead gantry signs for lane closures and speed restrictions, and tune in to local radio for updates. We will keep this live blog updated as the situation develops.
