M25 closures: motorway to shut for eight days with the project further delayed

Britain’s busiest motorway is closing for a total of eight days next month, with experts predicting “lengthy tailbacks” after National Highways announced that its renovation project for Junction 10 has been delayed by up to nine months due to "periods of extreme weather".

Over the weekends of 7-10 and the 21-24 March, the section of the M25 spanning Junction 10 for Wisley will close from 9pm on the Friday and reopen at 6am on the following Monday. This will allow for the demolition of several bridges, which will in turn make room for the construction of the nation’s first heathland bridge – something designed to allow the movement of not only pedestrians, but wildlife, too.

The RAC’s breakdown spokesperson, Alice Simpson, told Auto Express that the association forecasts “really lengthy tailbacks during the eight days of M25 closures. Friday 21 March coincides with England’s World Cup qualifying match against Albania at Wembley, meaning diversion routes are likely to be even more congested than usual.”

With this in mind, senior project manager at National Highways, Jonathan Wade, warned drivers to “only use the motorway if their journey is absolutely necessary”, saying that “unfortunately, it’s simply not possible to carry out this scale of infrastructure improvement without there being some degree of short-term disruption.”

If all of that wasn’t enough, Junction 10 is set to see another closure before March in the form of the on and off slip roads being cut off from 21 to 24 February, while the neighbouring A3 will close in both directions between the M25 Junction 10 and Cobham Roundabout over the weekend of 11-14 April.

Perhaps the icing on the very inconvenient cake for drivers is that National Highways has now announced that the completion date of the entire Junction 10 project, which was expected by the summer of this year, has been pushed back by around nine months to spring 2026.

Wade apologised to drivers, saying, “Periods of extreme weather in 2024 delayed some elements of our work, but since then we’ve worked hard to recoup that time and still complete the on-road elements on schedule.”

Why is the M25 closing?

The project at Wisley is set to be completed by spring 2026 at a cost to the taxpayer of a staggering £317 million (or perhaps even more now the project’s been delayed), and this series of M25 closures is to allow works that will completely reconfigure the troublesome Junction 10 roundabout where the M25 and A3 meet. 

These closures are the first time the M25 has shut during the daytime since it opened almost 40 years ago in 1986. However, National Highways says the improvements will not only “reduce congestion [and] provide safer journeys for thousands every day”, but also allow the installation of a nature bridge (also known as a heathland bridge) which will let wildlife cross from one side of the motorway to the other safely.

Nevertheless, National Highways is predicting “long delays” when the motorway is closed, with Senior Project Manager, Jonathan Wade saying: “Our advice is please only travel if absolutely necessary and make sure you give yourself extra time if you do choose to use the M25.”

Where is the M25 closure?

The next M25 closure will occur between Junctions 10 and 11 to facilitate improvements to the A3/M25 intersection at Junction 10. 

National Highways provides official diversion routes for each closure; these will be signposted, with full directions listed on the official project website. If and when a diversion takes drivers through London’s Ultra-Low Emissions Zone (ULEZ), those not behind the wheel of compliant cars will not be charged.

When is the next M25 closure?

Drivers can expect four sets of closures between now and the end of April: firstly, the sliproads at Junction 10 are set to close over the weekend of 21 to 24 February – you will still be able to drive on the M25, just not join or leave it at this junction.

Next, the M25 itself will close between Junctions 10 and 11 from Friday night to Monday morning on the weekends of 7-10 and 21-24 March; signposted diversions will be put in place by National Highways.

Finally, from 11-14 April, the nearby A3 will close between the M25 Junction 10 and Cobham Roundabout/A245.

Do not use sat-nav to avoid M25 traffic problems

Many motorists worried about traffic problems resulting from the M25 closures will be tempted to use their sat-nav systems to try and find a quicker route, but the official advice is not to do so. Jonathan Wade warned that a previous closure on the A3 had resulted in major traffic build-up in local villages as drivers tried to find their own diversion routes.

"We can't influence people in terms of taking the initiative themselves and just simply following what a sat-nav says, but please follow the signs." He said, going on to explain that there was "probably a greater risk of congestion by people just doing their own thing and thinking they can perhaps beat the signs and find a shorter or quicker route".

Motorists should avoid travel in the area if possible except for essential trips.

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