A hated 50mph limit and lane closures will remain on the M20 until NEXT summer – even though Operation Brock is being removed tonight.

National Highways says use of the contraflow system over the last two months has had a "knock-on effect" on work to upgrade the central reservation between Ashford and Maidstone.

Contractors were widening the middle of the motorway to allow the concrete barrier usually stored on the London-bound hard shoulder to be moved there.

But the implementation of Brock in early July meant that project had to stop – and has now pushed back the completion date to summer 2023.

Road bosses initially said using the contraflow system between Junctions 8 and 9 wouldn't delay the works, stating the scheme would be finished by January next year.

But when asked by KentOnline this week, a National Highways spokesman said: "Unfortunately, any deployments of the Operation Brock contraflow have a knock-on effect to progress of this safety work.

"We considered what work could still be done while the contraflow was in place.

"While some work has been done this summer, it was not possible to complete the work by January 2023 as originally planned.

"We were able to carry out some work but not enough to avoid moving the completion date."

Sean Martell, head of service delivery at National Highways, says storing the moveable barrier on the hard shoulder "was only a temporary measure".

"Moving the structure to the central reservation will allow the hard shoulder between Ashford and Maidstone to be reinstated to its original width," he said.

"We are grateful for people’s patience while the contraflow system has been in place; it has enabled us to keep Kent moving.

"We will remove the contraflow overnight on Saturday, with the M20 reopening on Sunday morning.

"We will however leave the barrier out on the London-bound carriageway for the safety of our workforce while we continue our work in the central reservation.”

National Highways says the moveable barrier will remain in place until spring "to act as a safety shield for our workers".

It will then be permanently moved into the central reservation, allowing a "second stage" of work to begin which is due to be completed next summer.

But a spokesman stressed the timings "are subject to change dependent on any future deployments of the contraflow".

From 8pm this evening, the authority will shut the coastbound stretch between Junctions 7 and 9 and the London-bound side between Junctions 9 and 8 to deactivate the contraflow.

Both carriageways will reopen at 6am tomorrow, but with only two lanes running on both sides along the 13-mile stretch.

National Highways says lane three on the coastbound side will remain closed to protect the workforce carrying out the work in the central reservation, while the concrete barrier will limit the London-bound route to just two lanes.

Last month, a furious driver called for Operation Brock to be removed after his Mercedes was written off in a crash with a lorry, but Ashford MP Damian Green said he believed the system is safe.