The Times:

It’s the busiest junction on the busiest motorway in the country. But at 9pm on Friday, the traffic will disappear completely from a five-mile stretch of the M25 as it closes for roadworks during daytime for the first time in its history.

The London Orbital will be shut in both directions between junctions 10 and 11 until 6am on Monday, as part of a £317 million engineering project to build a new interchange with the A3, improving safety, congestion, and even, according to National Highways, the local environment.

Up to 6,000 vehicles an hour bound for Heathrow, Gatwick and the Channel ports will be diverted to adjoining roads in Surrey, causing widespread traffic jams. Motorists have been advised to stay away.

They had better get used to the disruption. There will be a further four weekend closures between now and September, on dates yet to be decided, to allow work to continue. The aim is to complete it by summer next year.

Junction 10, known as the Wisley interchange, has become notorious for collisions, with the worst record on the M25. Vehicles are forced to back up on the A3 as they wait to join the motorway, at risk from other traffic speeding past. On weekdays, 300,000 vehicles pass through the junction.

Ten years in the planning, the Wisley interchange project is one of the most significant undertaken since Margaret Thatcher opened what she described as “the longest city bypass in the world” in October 1986. The critics promptly re-named it Britain’s biggest car park, due to its traffic jams.

What is happening to the M25?

On Friday night, once the traffic is halted, demolition crews will set to work removing the Clearmount bridleway bridge, which spans the M25, and installing a large gantry. They have been told that reopening the road in time for the start of the working week at 6am on Monday is non-negotiable.

The bridge is just one piece in a complex jigsaw puzzle which will involve enlarging both the M25 and the A3 from three to four lanes in each direction, and adding eight bridges. Some are needed because the junction is expanding — but there will also be four new bridges for cyclists, pedestrians and horseriders that will connect the surrounding landscape of woodland and heath. At the moment, this is effectively a no man’s land.

Each step will require the closure of the road beneath, as it is otherwise impossible to do safely. It took a 750-tonne crane to lift the 80-metre beams into position for Wisley Lane bridge.

The M25 was already shut overnight at the end of January to install Sandpit Hill bridge, the longest crossing at 91 metres. It will be shut again for a weekend in April for the installation of the new Clearmount bridleway bridge.

What are the diversions and alternative routes?

Jonathan Wade, the National Highways lead on the project, said last week that there would be heavy congestion and delays despite months of careful preparations. Traffic will be diverted onto the A3, A245 and the A320, a route of about 11.5 miles. Serious delays are inevitable because the alternative roads will not be able to cope with the extra traffic.

Drivers are being advised to avoid peak times and, if heading for Heathrow or Gatwick, leave plenty of extra time.

Steve Gooding, director of the motoring research charity the RAC Foundation, told Sky News: “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. 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.”

What will it do to the environment?

The roads cut through an area of rare heathland and ancient woodland, which is adjoined both by RHS Garden Wisley and the Georgian pleasure gardens of Painshill.

Nick Harris, chief executive of National Highways, has declared a highly ambitious goal: for the construction of new roads to leave nature in a better state than before the tarmac was laid. He said: “Roads need to be demonstrably environmentally sustainable, otherwise I would argue roads don’t have a good future.” In practice, this can involve offsetting the damage by buying depleted land elsewhere and restoring its biodiversity.

For the Wisley interchange project, restoration will focus on the immediate surrounding area.
Two years ago, this was a landscape of heathland and pine forests. Now it is a wasteland of mud and stumps — but the developers insist their plans will leave it in better condition than before.

While some trees were sacrificed for construction, the main purpose of cutting others down was to restore precious heathland which had been covered by commercial tree planting. As the heathland recovers, rare birds including nightjars, woodlarks and Dartford warblers are expected to return.

Later this year, the project will involve constructing the Cockcrow green bridge, the country’s first heathland bridge consisting of a 25-metre-wide wildlife corridor.

There will also be two underpasses built for toads, while local badgers have apparently been living in an artificial sett provided by National Highways.

To many, the M25 is a blot on the landscape, which pushed the boundaries of the metropolis deep into the countryside. But when it was built, it set standards which would have astonished the builders of Britain’s first motorways in the 1950s and 1960s. Landscape architects were involved throughout, with earth mounding and contouring to reduce the noise and mask the sight of moving traffic, and the planting of 2.1 million trees. Surviving members of the 1980s team shared their insights at events with National Highways ahead of the recent work for this project.

But Rebecca Lush, of the Transport Action Network campaign group, which has clashed with National Highways through legal challenges to new roads, believes that the project will neither solve congestion problems nor reduce environmental harm.

She said: “Widening the M25 is futile, as evidence shows it will just fill up again. The suggestion that building roads improves the environment is a laughable fantasy. You cannot replace veteran trees and ancient woodland with saplings, and most of the ones planted by National Highways die anyway.”


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