Work to move a motorway barrier built to reduce post-Brexit traffic disruption near Dover will cause delays for up to a year.
National Highways said there will be lane closures and a reduced speed limit on the M20 between junctions eight and nine from later this month until at least October as it moves a barrier used to help traffic flow when there are delays in the English channel.
Operation Brock is a contraflow system which enables vehicles heading to the Port of Dover or Eurotunnel terminal at Folkestone to queue on the motorway while allowing other traffic to keep moving in both directions.
It employs a movable concrete barrier that can be put in place over night.
The barrier was first deployed in December 2020, but is currently being stored on the hard shoulder.
National Highways plans to move the barrier to the central reservation.
Speed limits will be cut to 50mph along the 13-mile stretch of road while this happens.
There will also be several overnight closures.
The roads agency said the work, which involves an “extensive” drainage upgrade and new signage, will be carried out in phases and could take “up to 12 months”.
Steve Gooding, director of motoring research charity the RAC Foundation, said: “Drivers using the M20 corridor will be dismayed at this latest news which comes after years of disruption caused by a series of major projects including the initial installation of the barrier, smart motorway upgrades and the building of Junction 10A.
”Users of the M20 might reasonably be asking whether this latest set of works could have been carried out when the barrier was first put in, why they need to take so long, and what is being done to minimise disruption while the works are under way.
“The M20 clearly has to cope with a unique set of pressures but all those driving on this key route must be fervently hoping that this, the latest in a long line of disruptive works, is going to be the last for the foreseeable future.”
Operation Brock was supposed to be a temporary measure when it began in 2020 but it was revived in July.
The emergency traffic management powers were set to expire in October but were made permanent.