Part of the M20 will shut tonight as Operation Brock returns ahead of the summer holidays.

The contraflow scheme, which sees lorries heading to the continent queue on the coastbound side between Junction 8 for Leeds Castle and 9 for Ashford, will be redeployed overnight.

It means the motorway will be out of action from 8pm until 6am tomorrow from Junction 9 to 8 London-bound and Junction 7 to 9 coastbound.

The Brock system sees the London-bound carriageway operate as a contraflow with narrow lanes and a 50mph limit and is expected to remain in place throughout the summer holidays.

It comes as holidaymakers as well as spectators heading to the Olympic Games in Paris are expected to head through the county from July 13 until the middle of August.

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.

Bosses say any EU-bound HGVs not complying with the signs 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 Operation Brock queue if caught trying to bypass the M20 by using the M2/A2 at Brenley Corner.

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

Highways bosses are advising anyone who is planning to use the Eurotunnel and the Port of Dover to check with the travel operator before setting out, as well as allowing more time.

A new permit system will also be implemented in a bid to stop lorry drivers “rat running”.

The Kent and Medway Resilience Forum (KMRF) says the passes, which will be issued to truckers at the front of the Operation Brock queue, will “prevent lorries from bypassing the control measures”.

They will be checked on the A20/B2011 Courtwood Interchange in Dover and, if truckers do not have the permit, they will be told to turn around and join the Brock queue.

Simon Jones, strategic lead of the KMRF, said: “We are doing everything we can to find more effective ways to manage traffic heading through Kent to cross the Channel, as we know that the impact of severe disruption on local communities and in Dover itself can really affect people’s lives and businesses.

“One thing that could help is stepping up measures to ensure that freight drivers stick to the plan, and cannot circumnavigate the queues.

“This only adds to congestion, particularly in the centre of Dover.

“The message from KMRF to freight drivers is ‘no permit – no access to Port of Dover’...”

“However, these freight permits are not a ‘fix all' solution.

“There is no doubt that, in busy periods, the situation on the roads heading through Dover remains extremely fragile.

“With a busy summer ahead, and the introduction of entry-exit system [EES] checks later this year, we are doing everything we can to prevent further disruption.”

In a further statement, KMRF, which is made up of a number of authorities including Kent County Council, said traffic flows will be “continually monitored throughout the holiday period”.

It said: “To ensure freight drivers have followed the correct route, all freight heading to the Port of Dover would have to leave the A20 at the Courtwood Interchange, at the junction of the A20 and the B2011, where their permits would be checked at the end of the slip road.

“If they have complied, they will be allowed to re-enter the Dover TAP queue on the A20 and continue their onward journey to the port.

“The message from KMRF to freight drivers is ‘no permit – no access to Port of Dover.’

“Local HGVs and deliveries will not be pulled off the A20, but allowed to continue their journey, with passenger and local traffic, onwards into Dover.

“Those Kent hauliers that qualify for a ‘local haulier permit’ will be sent this ahead of the busy summer period.

“There is no need to apply for a local licence as, if you fall within the catchment area, KMRF already has your details.

“Operation Brock will be removed as soon as possible, once the impact of disruption has reduced.”