The Operation Brock system installed to manage expected traffic chaos in Kent after Brexit will now itself cause a year of disruption as the barrier is moved from the edge to the middle of the motorway.
The scheme, costing an initial estimated £35m, was designed to reduce blockages on the roads to and from the Channel ports with a contraflow system for queueing lorries held up by border and customs requirements.
Steel sections originally in use were replaced by a movable concrete barrier from 2020, meant to minimise disruption by reducing installation and deactivation times.
Now that barrier itself needs moving, according to National Highways, on to the central reservation while it tackles drainage issues on the motorway.
Work to move and store the barrier will see overnight closures of parts of the M20, which runs from London to Folkestone, starting at the end of January, with lanes closed on both sides for an expected 40 weeks.
The concrete barriers run on a 16-mile stretch of the Kent motorway, and are currently stored on the London-bound hard shoulder.
While queues never reached the worst-case predictions of up to 13,000 lorries, the system was briefly revived last July when the start of the school holidays raised fears of congestion around the Channel ports.
Last October it was revealed that the government was retaining the emergency powers to implement the system in case of future border disruption.
National Highways said it would need to carry out an extensive drainage upgrade and ground work to allow the Brock barrier to be stored on the central reservation. Work could last up to 12 months, it said.
Confusingly, the Brock barrier will be placed on the motorway to seal off the necessary works until October. National Highways said this will “not mean the Brock contraflow system will be active” – but it could be. The measure “will provide a more efficient and cost-effective way of being able to deploy the contraflow quickly and effectively should it be required”, the agency added.
Reduced speed limits will also be in place on parts of the M20 for the duration of the works.
Councillors said they do not fully understand the reasons behind the latest developments in Operation Brock, whose deployment has long been a source of irritation for local people and motorists.
Ashford borough council’s deputy leader, Paul Bartlett, told Kent Online he believed there were safety concerns, adding: “It seems extraordinary for it to take 12 months. They’ve sent a very long letter out about it but it doesn’t give a great deal of information about why they are doing it.”