An “increasing number” of drivers are “choosing to ignore” the official diversion route around the M25 closure, highways bosses have warned.

National Highways say they are making “good progress” to install a new gantry and a new gyratory bridge between junctions 9 and 10 of the motorway.

The seven-mile stretch, through Surrey, closed at 9pm on Friday and is due to reopen at 6am on Monday, while the work takes place.

A planned 19-mile diversion route, which sends vehicles through parts of Surrey and Greater London, is in place during the closure.

However, National Highways say some drivers are not sticking to the route and are instead following another route specified for freight vehicles.

Simon Elliott, National Highways senior project manager, said: “It is important that drivers follow the diversion route in place.”

Image:
A map showing the M25 closure and the diversion route between junctions 9 and 10 in May 2024

The official clockwise route for non-freight vehicles involves drivers coming off at junction 8, before travelling along the A217, the A240, the A24, and the A3, before rejoining the M25 at junction 10.

Freight vehicles should continue on to junction 9 and travel towards Chessington on the A243 and then back towards junction 10 via the A307.

However, Mr Elliott said non-freight drivers were also using this route.

What are the diversion routes?

Diversion route clockwise for all but over-height vehicles:
Leave M25 at junction 8, A217 (Reigate). Follow the A217 London, Sutton, (A240) Kingston. After 3½ miles turn left onto the A240 Epsom, Kingston. After 3 miles at the Esso roundabout, turn right onto the A24 (A240) Kingston. Continue for 3 miles and turn left onto the A3 Portsmouth, Guildford. Continue for 9½ miles to the M25 and re-join the motorway at junction 10.

Diversion route anticlockwise for all but over-height vehicles:
Leave M25 at junction 10 to join the A3 towards London. After 9½ miles at the Hook interchange leave the A3 turning right onto the A240 Epsom, Reigate. Continue for 3 miles to the Esso roundabout and turn left onto the A240 Reigate. Continue for 3 miles then turn right onto the A217 Reigate, M25. After 3½ miles turn left to re-join the M25 motorway at junction 8.

“Coming off at junction 9 means non-freight drivers will end up travelling behind or alongside HGVs which is something we are actively trying to avoid and is likely to have a negative impact on travel times, congestion and the communities they pass through,” he said.

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This weekend’s closure is the second of five planned closures of the motorway, and comes after a section between junctions 10 and 11 was shut in March.

On that occasion, fears diversion routes would become overwhelmed proved unfounded, as traffic levels were more than two-thirds lower than normal after a widespread awareness campaign.

The diversion takes drivers through A roads. Pic: PA
Image:
The diversion takes drivers through A roads. Pic: PA

National Highways say this weekend’s closure is to allow for the installation of a new bridge between junction 9 and junction 10.

Read more:
Everything you need to know ahead of the M25 closing
Aerial pictures show calm amid M25 gridlock fears

The previous closure was to allow for the demolition of Clearmount bridleway bridge between junction 10 and junction 11 and the installation of a large gantry.

Three more weekend closures of the M25 are set to take place between August and the end of the year.