The U.K. intends to adopt its full no-deal Brexit border plan to avoid traffic chaos when it completes its split from the EU in 2021, even if the two sides sign a free-trade agreement.

Announcing a month-long consultation on the blueprint, the Department for Transport said it will effectively resurrect Operation Brock, a traffic management system designed to limit tailbacks around Dover and Eurotunnel, two key trade arteries for Britain.

“Something akin to Operation Brock will need to be confirmed for use at the end of the transition period,” the Department said in a statement, referring to the program which would have been used if Britain had left the EU without a deal in 2019. Disruption at the cross-Channel ports is “clearly a possibility,” it said.

Truck drivers that don’t comply with the system could face a fine of 300 pounds ($391), according to the government’s plan.

Britain is bracing for an economic shock when the Brexit transition period finishes at end of the year, as commerce with its largest trading partner becomes subject to new red tape and paperwork. The U.K. government fears trucks moving from Britain to the EU won’t have the right customs forms, meaning they could be stopped by French officials and cause major supply chain disruption.

Trucks without the right documents risk “being held at port until the relevant paperwork has been provided, and in some circumstances having their goods seized or destroyed,” the government said in the consultation.

It said analysis from October 2019, when it appeared Britain may leave the EU without a deal, showed hauliers were poorly prepared for the new customs checks, and, due to coronavirus, it would be prudent to assume that’s still the case now.