A stretch of the M25 will be closed for a full weekend for the first time next week and National Highways is warning drivers to “only travel if necessary” and to expect huge delays.

The motorway will be closed in both directions from junction 10 (A3 Wisley) to junction 11 (A320 Chertsey Interchange) from 9pm on Friday, 15 March to 6am on Monday, 18 March. 

National Highways says the road will close so it can demolish the bridleway bridge at Clearmount and install a large gantry.

The work will also increase the number of lanes at junction 10, which, National Highways said, will “make journeys safer and improve traffic flow”. Entry and exit roads to Wisley, Pyrford, Old Byfleet and RHS Wisley will be made safer, it said, and pollution will also be reduced. 

Jonathan Wade, project lead for National Highways, said: “Drivers should only use the M25 if their journey is absolutely necessary. This is the first of five full closures of one of the busiest junctions on our road network.

“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.

“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.”

As part of National Highways' programme to improve junction 10, five full closures are set to take place between now and September 2024. 

The government body has not yet announced the exact dates of the four other closures, but the next one will take place in April to install the new bridleway bridge at Clearmount. Closures will not take place during holiday periods, it said.

Future closures will include the installation of the new Cockrow Green Bridge - the UK’s first heathland bridge, which will connect the Ockham and Wisley commons and form a natural and safe corridor for local wildlife.

Between 4000 and 6000 vehicles travel between junctions 9 and 11 between 10am and 9pm on a weekend, National Highways said, and it warned that travel to airports such as Heathrow and Gatwick could be affected.