Drivers are being warned to expect delays as a planned M25 closure starts on Friday.

The AA said many major roads in the South East will be “incredibly busy” as National Highways shuts the motorway between Junctions 10 and 11 in Surrey from 9pm on Friday to 6am on Monday.

This will be the third of five weekend closures of the M25 – which encircles London – as part of a £317 million project to improve Junction 10.

A graphic showing diversion routes during the planned M25 closure
(PA Graphics)

Motorway vehicles will be directed along a diversion route on A-roads.

Among the people affected will be many of those travelling to, from and between the UK’s two busiest airports, Heathrow and Gatwick.

It could also disrupt many journeys to Dover by England football supporters embarking on cross-Channel trips before driving to Berlin for Sunday’s Euro 2024 final.

AA patrol of the year Chris Wood said: “With many football fans changing their plans following England’s victory over Holland, it’s likely to be incredibly busy in and around London.

“We advise drivers to plan their journey accordingly, avoiding the west side of the M25 if possible, and to check ferry and tunnel operators’ websites for updates before setting off.

“Prepare your vehicle by checking oil and coolant levels, tyres and make sure you have enough fuel or electric charge to cover the planned diversions.”

There were fears of severe congestion on diversion routes ahead of the first two planned M25 closures in March and May, but many drivers followed advice to avoid the area, meaning long hold-ups were avoided.

National Highways senior project manager Jonathan Wade 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.”

Jonathan Wade, senior project manager for National Highways, on a site visit
Jonathan Wade, senior project manager for National Highways, urged drivers to ‘ignore your satnavs’ (Gareth Fuller/PA)

National Highways is concerned that satnavs could direct some drivers on to minor roads after leaving the M25, creating gridlock in residential areas.

Shutting the motorway this weekend will enable the construction of a new bridge near Junction 10.

The March closure was the first planned daytime shutdown of the M25 since it opened in 1986.

The project, due to be completed in summer 2025, will increase the number of lanes at Junction 10, which is one of the UK’s busiest and most dangerous motorway junctions.

Between 4,000 and 6,000 vehicles normally use the M25 between Junctions 9 and 11 in each direction every hour from 10am until 9pm at weekends.

The final two weekend closures as part of the project will take place later this year.