A 50mph limit and narrow lanes will remain on the M20 for six more weeks - even though Operation Brock has been removed.

National Highways has been widening the central reservation between Ashford and Maidstone since January last year at a cost of £20m.

But deployments of the dreaded contraflow system have pushed back the works by nine weeks - and bosses now say the scheme won't be finished until the summer holiday.

Contractors are upgrading the middle of the motorway between Junctions 8 and 9 to allow the concrete barrier used to make the contraflow to be moved there.

In order to protect the workforce, the barrier is currently set up in the middle of the London-bound carriageway and drivers are restricted to just 50mph.

Bosses say their teams are working on the project “24 hours a day, seven days a week” to minimise disruption and complete the work before the busy summer holiday period.

But while Brock is not expected to be deployed between now and the project’s end, they admit any such action would result in works being delayed again.

The scheme will see the moveable barrier usually stored on the London-bound hard shoulder housed in the central reservation – and while it will still require an overnight closure of the motorway to deploy, the work will make the hard shoulder wider.

Of the total 10.6-mile stretch of road affected, work has been completed on 10.3 miles with the final 450m to be finished in the next few weeks.

Also included in the upgrades is a new drainage and CCTV system of 67 cameras – which drivers may have spotted as it is currently being housed in a long length of purple pipe on the roadside.

Narrow lanes are currently in place on most of the London-bound stretch between Junctions 9 and 8, while a small section on the coastbound side near Hothfield is also covered by the 50mph limit.

Reacting to the latest hold-up, Ashford MP Damian Green says he thinks it is "very important" the work is completed before the schools break up for the six-week summer holiday, which starts on Friday, July 21.

The most recent delay to hit the project came at the end of May when Brock was deployed over half-term.

Mr Green said: "The investment will be worthwhile if it means the barrier can be put on and, equally importantly, taken away very quickly when disruption occurs in the future.

"Dover and the Channel Tunnel flowed freely during half-term, which means that Brock served its purpose.

"If they had backed up, the inconvenience for those of us in Ashford would have been worse, as it used to be when Operation Stack was in force."

National Highways says the 50mph limit is being monitored by average speed cameras, with enforcement carried out by Kent Police.

In a statement, a spokesman said: “Now the Operation Brock contraflow has been removed we’ll be carrying on with our £20m scheme to move the concrete barrier to its permanent position in the central reservation, which will allow quicker deployment of the Brock contraflow at times of cross-Channel disruption.

“To minimise disruption and accelerate completion of the scheme, National Highways will undertake work 24 hours a day, seven days a week.

“The Christmas and half-term deployment of Brock has unfortunately resulted in a nine-week delay to the scheme.

“Now that we have switched to working 24/7 we’re confident the barrier works will be complete by the summer holidays.”

The deployment of Brock over the May half-term drew criticism from Kent County Council’s leader, Cllr Roger Gough.

He said the decision to implement the system was unwelcome and raised questions about how the contingency measures were considered necessary for that Bank Holiday weekend but not for the two previous ones.

Speaking at the county council’s annual meeting, he said: “We have been pleased to see two consecutive holiday weekends without the need for Operation Brock but then immediately after that… because of high coach volumes at Easter, Operation Brock was needed.

“We now see strong demand for both the Port of Dover and Eurotunnel for the Whitsun weekend, which is good in one sense because demand has risen to pre-pandemic levels - but the consequence of this is disappointingly that Brock is once again being needed to assist with the fluidity at the gateway to Europe.

“This is a reminder of the scale of the pressures we still face with the consequent impact on residents and businesses, the more so in the light of the coming - if not delayed - implementation of the European Union’s entry-exit system.

"We are continuing to push the Department for Transport and other government departments who we are deeply engaged with to address these issues.”

In April, the government announced post-Brexit checks on potentially harmful goods coming to the UK from the EU are to be reduced and simplified.

The new Border Target Operating Model involving fewer checks and bureaucracy, and more digitisation - backed by more than £1bn in funding - has been announced to "minimise trader burdens and maintain border security while remaining aligned with international standards".

South Thanet MP Craig Mackinlay says more imaginative solutions were required, such as checking passports on coaches before they got to Dover.

“The problem with Dover is that it is a small port,” the Conservative said.