Drivers are being warned of massive delays when the M25 shuts in both directions next week in an unprecedented move.

The closure between junctions 10 and 11 in Surrey on the UK’s busiest motorway could cause chaos.

But when exactly is it going to be shut, where are the diversion routes and why is it happening? Here’s everything you need to know.

When is the closure and how long will it last?

It’s from 9pm on Friday 15 March to 6am on Monday 18 March and covers the five-mile stretch between the junctions in both directions.

What is the diversion route?

Here’s the diversion route that’s been outlined by National Highways, which maintains England’s motorways:

Weather warnings issued for parts of UK – Eurostar warns of more delays as trains resume

Almost 60 more flights cancelled after further problems with air traffic control at Gatwick

Willie Walsh: Boss of airlines group says air traffic control firm NATS should pay for ‘shocking’ airport chaos

You can see it on the map below:

How bad could it be?

It’s the first scheduled daytime all-lanes shutdown on the M25 since it opened, so it’s not yet known exactly how big delays are going to be.

This section of the M25 normally carries between 4,000 and 6,000 vehicles in each direction per hour from 10am until 9pm at weekends, so the disruption caused by the works is expected to be significant.

More than 200,000 vehicles are expected to be affected, including many travelling in and out of London, and to and from Heathrow and Gatwick airports and Channel ports.

What advice has been issued?

“Drivers should only use the M25 if their journey is absolutely necessary,” says Jonathan Wade, National Highways project lead.

“This is the first of five full closures of one of the busiest junctions on our road network,” he adds.

“We have spent months planning for these closures and making sure there are diversion routes in place, but there will still be heavy congestion and delays.”

‘You ain’t seen nothing yet’

“For drivers who’ve already had their patience tried by the queues at the junction 10 works, the phrase ‘you ain’t seen nothing yet’ springs to mind,” warns Steve Gooding, director of motoring research charity the RAC Foundation.

“National Highways’ plea for people to avoid driving in the area applies not just to trips on the M25, but also to those on surrounding local roads onto which the M25 traffic will be diverted,” he adds.

“The hope must be that drivers take great care, however frustrating the delays and disruption might be.

“The last thing we need is shunts or crashes, however minor, because the slightest mishap will compound the misery.”

Read more from Sky News
Luxury hotel offers free night’s stay if it rains too much
‘Absolutely gross’ maggots force flight to make U-turn

A London Gatwick Airport spokesperson told Sky News: “Passengers driving to the airport are advised to check diversion routes before they travel and allow extra time for potential delays.

“Gatwick’s train station is well connected and is a great alternative option for people travelling to the airport this weekend.”

Sky News has contacted Heathrow Airport for comment.

Why is it happening?

Government-owned company National Highways said the action is necessary to enable a bridge to be demolished and a new gantry to be installed as part of a £317m improvement project.

National Highways says the project will increase the number of lanes and make it easier to enter and exit the M25 at junction 10, which is one of the UK’s busiest and most dangerous motorway junctions.

“These improvements will bring long-term benefits to drivers who pass through this stretch of the M25, not to mention pedestrians, cyclists and horse riders who will also see positive changes in the area,” says its project lead Jonathan Wade.

Is the closure a one-off?

No – it’s just one of five planned full closures between the junctions.

Be the first to get Breaking News

Install the Sky News app for free

The other four closures are expected to take place up to September, according to National Highways, but their dates have not yet been confirmed.

The project began in summer 2022 and is expected to last three years in total.

Related posts:

Strawberry supermoon: Last of night sky spectacles this year approaches Why the risk-benefit balance of AstraZeneca jab for young people has shifted ‘Pitiless’ man accused of helping murder son tells court he ‘probably’ valued lover over child Penny Mordaunt is latest Tory to enter leadership race to replace Johnson as prime minister Nearly one in four 16-year-old girls using NHS mental health services Epsom College headteacher died of shotgun wound to chest – and daughter shot in head Just 2% of pupils study books by women for GCSE English, study suggests Hunt for 20-year-old released from prison in error Man who killed golf greenkeeper with horseshoe jailed for 21 years Nicola Bulley’s family criticise ‘wildly inaccurate speculation’ over her death as inquest concludes Police station cordoned off after suspected WW2 grenade handed in Around 100,000 people attend pro-Palestine protest in central London