A five-mile stretch of the M25 will be closed in both directions over three days next week, with drivers warned of huge delays.
National Highways said the unprecedented closure of the UK’s busiest motorway – the first of five between now and September - was necessary in order to demolish a bridge and install a gantry.
The closure between junctions 10 (A3 Wisley) and 11 (A320 Chertsey Interchange) from 9pm on Friday 15 March through to 6am on Monday 18 March prompted National Highways to warn motorists to only travel if necessary.
The Junction 10 improvement scheme will see an increase in the number of lanes in an effort to make journeys safer and improve traffic flow.
National Highways said it should also make it easier and safer to enter and exit the M25 and provide safer entry roads for Wisley, Pyrford, Old Byfleet and RHS Wisley.
It will also reduce the pollution caused by traffic jams.
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.”
The carriageway between junctions 9 and 11 carries between 4,000 and 6,000 vehicles per hour in each direction between 10am and 9pm on a weekend.
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.
Later this year, National Highways will also look to install the new Cockcrow Green Bridge. This will be the UK’s first ever heathland bridge connecting Ockham and Wisley commons for the first time and provide a safe, natural corridor for local wildlife.