National Highways has revealed the date for its third planned weekend closure of part of the M25, sparking concerns of summer traffic mayhem.

The finished J10 improvement scheme is expected to open to traffic in summer 2025

The UK’s busiest motorway will be closed between junctions 10 and 11 in Surrey from 9pm Friday 12 July to 6am Monday 15 July 2024, enabling the construction of a new bridge on the roundabout at junction 10 as part of a £317m improvement project.

As with the previous two closures, drivers are again warned to expect delays and only travel if necessary.

National Highways has also urged drivers to follow its travel advice instead of sat-nav diversions, which it says will be key to reducing congestion.

Local residents, holidaymakers, concertgoers and sports fans should plan their journeys in advance and make sure they allow extra time or make alternative travel arrangements.

The local diversion route is the same for both directions. Drivers heading from junction 10 to junction 11 will need to follow the northbound A3 to Painshill Junction, A245 towards Woking, and then A320 to M25 Junction 11.

Those travelling from junction 11 to junction 10 are being advised to take the A320 south towards Woking, A245 towards Byfleet and Painshill junction, then the southbound A3 to junction 10.

National Highways have also advised drivers that heading around the M25 via the north stretch may actually be quicker.

It’s the third of five full weekend closures of the M25 planned for this year. July’s closure will see a new bridge, consisting of 68 beams, each weighing 16 tonnes, and another four beams weighing 40 tonnes, installed as part of ongoing work to make journeys safer and reduce pollution. The previous closure in May saw identical work being carried out on the eastern gyratory.

The initial closure, carried out in mid-March, heralded the first scheduled daytime all-lanes shutdown on the M25 since it opened in 1986. While the closure had been expected to bring the “worst traffic jam ever”, delays were largely minimal due to many drivers avoiding the area or rethinking plans, and the Surrey section reopened to traffic early after work was completed eight hours ahead of schedule.

Jonathan Wade, national highways senior project manager, said: “The previous two closures have gone well with significant progress being made during both.

“We would urge all drivers to follow the official diversion route as this is the best chance of reaching your destination in good time. Please ignore your satnavs and follow our diversion route instead.”

RAC Breakdown spokesperson Alice Simpson said: “With most drivers following the official advice, major congestion was averted during previous M25 closures and there’s no reason why the same can’t happen this time. Drivers should follow the signed diversion routes which have been designed to keep traffic flowing as much as possible.

“It’s worth remembering that the closure coincides with the finals at Wimbledon, so anyone planning on driving to this should anticipate a far longer journey or look at whether there’s a viable public transport alterative. For anyone who needs to drive – whether that’s to get to an event or to one of the London airports – checking their vehicles are ready for a longer trip is really important. Breakdowns can quickly lead to traffic queues, and it’s often the case that roadside patrols, including our own, end up sitting in jams trying to reach people. Ensuring oil and coolant levels are where they need to be, and checking tyres are in good condition and properly inflated, can dramatically reduce the prospect of breaking down in the first place.”

The Junction 10 improvement scheme will enable an increase in the number of lanes to make journeys safer and new junction layout to improve traffic flow. It will also make it easier and safer to enter and exit the M25, and reduce the pollution caused by traffic jams.

A further two M25 closures are due by the end of the year. The finished scheme is expected to open to traffic in summer 2025.

For more information about the closure and the project, please click here.