The M20 will shut tonight as the Operation Brock contraflow is deployed ahead of a busy bank holiday weekend.

The route will close between Maidstone and Ashford to allow the scheme to be implemented.

It is being deployed on a 13-mile section of the motorway between Junction 8 for Leeds Castle and Junction 9 at Ashford.

This is ahead of the Bank Holiday weekend due to the heavy volume of traffic expected.

The M20 will be closed – London-bound from Junction 9 to 8 and coastbound Junction 7 to 9 – overnight from 8pm tonight to 6am tomorrow.

National Highways says fully signed diversion routes will be in place while the M20 is closed overnight. These times have been chosen to minimise disruption to road users, bosses say.

The Brock contraflow will be in place when it reopens tomorrow and all signs should be followed.

Once the barrier is in place, all HGVs heading for the Port of Dover or Eurotunnel must follow the signs to join Operation Brock at M20 junction 8.

Any EU-bound HGVs not complying with signage and trying to use another route to Eurotunnel or the Port of Dover risk a fine of £300.

They will also be sent to the back of the queue by police or enforcement agents.

This includes trying to bypass the M20 by using the M2/A2 at Brenley Corner.

All other coast-bound traffic – including local freight and car drivers heading for the continent – should follow the signs and cross over to enter the contraflow on the M20 London-bound carriageway.

A National Highways spokesman said: “Anyone planning to use Eurotunnel and the Port of Dover is advised to plan their journeys and check with the travel operator before setting out.

“They should also allow more time for their journeys and ensure they are prepared for delays, so should have plenty of fuel, warm clothes, and supplies such as food and drink.”