Drivers are being warned of severe delays as the M25 motorway is closed in both directions this weekend for an unprecedented time.

The closure between junctions 10 and 11 in Surrey, Britain’s busiest motorway, is likely to cause chaos.

Daryl Jordan of Woking Borough Council said Byfleet Road, near junction 10, was “clogged up” on Friday afternoon.

“This is dividing people,” he added.

“When you work full time and then you come home from get off work tonight and you’re thinking ‘I’ve got to fill up the fridge’ and you can’t even get into your own village. It’s going to be a nightmare.”

But, how long will this section of road be closed, where will the diversion be and why is this happening? Here’s everything you need to know.

When does it close and for how long?

The closure begins at 9pm on Friday, March 15 and the road will be closed until 6am on Monday, March 18, covering a five-mile stretch between junctions 10 and 11.

What is the diversion route?

Here are the diversion routes planned by National Highways, which maintains Highways England:

• From Junction 10 to Junction 11: A3 northbound to Painshill Junction, A245 towards Woking, then A320 to M25 Junction 11
• Junction 11 to Junction 10: A320 southbound to Woking, A245 to Byfleet and Painshill junction, A3 southbound to Junction 10.

You can see it on the map below:

Here are some Google Maps screenshots showing part of the road along the diversion route:

sat nav warning

Drivers are being urged to ignore sat navs and only follow official diversion routes to prevent traffic jams during the “unprecedented” lockdown.

The extent of disruption will depend in part on whether drivers stick to official diversions, said Jonathan Wade, head of state highways projects.

“How many people will actively try to use satellite navigation?” he told the Palestinian News Agency.

“If people just go about their business and think they can get around the signs and find a shorter or faster route, the risk of congestion may be greater.

“This will cause further congestion at some key junctions so please avoid doing this if possible.”

Daniel Kitteridge, senior project manager at National Highways, said: “If people move off our prescribed diversion routes, it creates additional problems on different parts of the road network.

“Most of the time these are local roads so this does impact residents in those particular areas.

“That’s why we’re trying to encourage people not to follow satnavs.

“Stick to the prescribed diversion route which will better suit your journey.”

How bad can it be?

This is the first planned daytime full lane closure of the M25 since it opened, so it’s unclear exactly how serious the delays will be.

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

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

What advice has been issued?

Jonathan Wade, head of the National Highways Programme, said: “Drivers should only use the M25 when absolutely necessary.”

“This is the first of five complete closures at one of the busiest junctions on our road network,” he added.

“We have spent months planning these closures and ensuring diversions are in place, but significant congestion and delays are still occurring.”

“Motorists should decorate their bathrooms”

The head of the state-owned company also advised motorists to find things to do at home, such as “Decorate the bathroom” or “playing in the garden” before closing.

Wade said the region’s response to the lockdown would depend in part on whether drivers adhere to official diversions, but he urged people to avoid traveling altogether.

“If you can, avoid this area completely,” he told The Independent’s daily travel podcast.

“Either avoid traveling altogether or find something to do at home, decorate the bathroom or something, I don’t know, or play in the garden.

“If you have to go, take the train, walk, bike.

“If you can, avoid driving around these diversion routes.”

airport warning

People traveling to Gatwick and Heathrow airports may also be affected by the closure.

Heathrow advises passengers planning to use this section of the M25 to allow extra time before departure.

Their statement added: “Passengers using public transport should also note that Airline (between Heathrow and Gatwick) and Airrail (RA2) will be operating modified timetables this weekend, Please check with your carrier for the latest information.”

A spokesman for London Gatwick Airport told Sky News: “Passengers driving to the airport are advised to check diversion routes before traveling and allow extra time for possible delays.

“Gatwick train station is well connected and is a good option for people heading to the airport at the weekend.”

“You didn’t see anything”

Steve Gooding, director of automotive research charity the RAC Foundation, said: “For drivers who have queued at Junction 10 to test their patience, the words ‘you didn’t see anything’ will come to mind. In my mind.”

He added: “National Highways is urging people to avoid driving in the area, and this applies not only to journeys on the M25, but also on surrounding local roads where M25 traffic will be diverted.”

“However frustrating delays and disruptions may be, we ask drivers to exercise extreme caution.

“The last thing we need is a shunt or a crash, no matter how minor, because the slightest accident can exacerbate suffering.”

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Why does this happen?

State-owned company National Highways said action was necessary to remove a bridge and install new gantry as part of a £317m improvement project.

The National Highways Agency said the project would increase the number of lanes and make it easier to enter and exit the M25 at junction 10, one of the busiest and most dangerous motorway junctions in the UK.

Project leader Jonathan Wade said: “These improvements will bring long-term benefits to motorists traveling on this section of the M25, not to mention pedestrians, cyclists and horse riders who will also see Positive changes in the area.”

Is the closure a one-time thing?

No – this is just one of five planned total closures between intersections. Other dates have not yet been determined.

Mr Wade said: “Three of the closures will be between junctions 10 and 11 (A320) at Chertsey… two of them will be at junction 9 at Leatherhead and 10 at Wisley between intersections.”

He said dates for later phases would be announced in due course and motorists would be given adequate notice.

“We’re not just going to throw them at people,” he said, adding that they would be conducted between May and December.

The project begins in the summer of 2022 and is expected to last a total of three years.