In a move affecting millions, the M25 is set to have its first-ever planned full closure in the daytime – with drivers being warned to only travel if necessary.

National Highways will shut the M25 in both directions between junctions 10 (A3 Wisley) and 11 (A320 Chertsey Interchange) from 9pm on Friday, March 15, to 6am on Monday, March 18, to demolish the Clearmount bridleway bridge and install a very large gantry.

Other areas of the M25 and surrounding motorways will also feel the impact of closure with heavy congestion expected across the home counties.

People travelling to Gatwick and Heathrow airports, as well as Eurotunnel and the Port of Dover may be affected.

Those with tickets to concerts, sports events or other activities travelling to London and surrounding areas should also plan their journeys well in advance and make sure they allow extra time or make alternative travel arrangements.

It has sparked fears of traffic chaos, with Steve Gooding, director of motoring research charity the RAC Foundation, telling The Times: “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 on to which the M25 traffic will be diverted.”

Bosses behind the scheme hope the major project can make journeys safer and reduce pollution.

This will be the first of five closures between now and September 2024 – prompting National Highways to warn motorists of long delays and to only travel if necessary.

The next full closure of the M25 is due to take place in April to allow for the installation of the new Clearmount bridleway bridge. Dates are subject to change.

Jonathan Wade, National Highways project lead, 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.”

Drivers can use real-time traffic information for England’s motorways at trafficengland.com as well as X (Twitter) updates by following @NationalHways.

Any closures will also be visible on satellite navigation.

The Junction 10 improvement scheme will see an increase in the number of lanes to make journeys safer and improve traffic flow.

It will also make it easier and safer to enter and exit the M25, provide safer entry roads for Wisley, Pyrford, Old Byfleet and RHS Wisley and will reduce the pollution caused by traffic jams.

Without a full closure of the M25 at this junction, it would be impossible to safely demolish the overbridges and install the new gantry.