Plans to keep traffic moving on the M20 in the event of disruption caused by Brexit-related delays at Channel ports are expected to cost the taxpayer £30m.

Highways England says the estimated costs will cover the design, build and initial operation of the scheme for up to six months.

It has also confirmed that implementing the scheme for a contraflow along the motorway between junctions 8 and 9 could take 14 days.

The time estimate for putting the scheme into operation was first reported by KentOnline in July.

According to a Freedom of Information request made by The Guardian, the agency said: “This duration is due to the one-off installation of [a] temporary steel barrier and the traffic management signs.

"We are developing plans that may enable faster deployment using alternative barrier types, this of course is dependent on a safe and suitable method being found.”

Kent County Council leader Cllr Paul Carter (Con) said he was concerned by the length of time potentially involved but had been told that Highways England was refining the scheme.

“They have got to make sure the roads keep moving. Taking 14 days to implement Operation Brock is not a sensible plan and, when I queried it, I was assured that this was not the case and that they had refined their plan.”

Meanwhile, Kent Chief Constable Alan Pughsley has played down reports there might be civil unrest after Brexit.

At a performance and delivery board meeting this week, he said: "Brexit is much more wider than some people who say 'the world is going to end on March 29' I don't share that view.”

"From a European Union point of view, I think we will be in the same position as we are now. Whatever the process looks like, I think it will be the same because we will still have to be policing the borders with regard to criminality coming in or out to Europe.”