The M25 anticlockwise exit at junction 15, where the motorway meets the M4 near Heathrow Airport, will be shut for 14 hours over the weekend, from 8pm on Saturday, October 24, to 10am on Sunday, October 25. National Highways has confirmed a signed diversion route will be in place, but drivers have been warned to allow extra time, especially between 8am and midday on Sunday, when traffic is expected to be particularly heavy.
Diversion route via M4 and junction five
Drivers who normally use the anticlockwise exit will be directed onto the M4 westbound towards junction five at Langley. From there, they must turn around at junction five before re-joining the M4 via junction 4b. This diversion is expected to add significant time to journeys, particularly for those heading to Heathrow Airport.
Heathrow Terminals 2 and 3 are accessed via the M4 and junction 15 area, while Terminals 4 and 5 are reached via M25 junction 14. Passengers travelling to the airport should check the route to their specific terminal before setting off.
Preparatory work for bridge repairs
The same motorway exit also closed last weekend as part of preparatory work ahead of repairs to two major bridge expansion joints. Further work is planned for 2027, though no specific dates have been announced. The current closure is part of ongoing maintenance to ensure the safety and longevity of the motorway infrastructure.
National Highways has not provided specific estimates for how many drivers will be affected, but the closure is expected to impact thousands of vehicles, given the M25's role as a key route to Heathrow and the surrounding areas.
Advice for passengers and drivers
Passengers travelling to Heathrow are advised to check the route to their specific terminal and allow extra time for their journeys. National Highways recommends using alternative routes where possible and following the signed diversion signs. The agency has also reminded drivers to plan ahead and stay updated on traffic conditions via live travel apps or radio broadcasts.
The closure is part of a broader programme of maintenance work on the M25, which is one of the busiest motorways in the UK. The repairs to the bridge expansion joints are essential to prevent further deterioration and ensure safety for road users. Drivers are urged to remain patient and follow all signage and instructions from traffic officers.
