On the day the U.K. makes its final break with the European Union, the ports are clear of truck backups, goods are moving smoothly and grocery-store shelves are well stocked. Even so, U.K. businesses that rely on some 1.2 billion pounds ($1.6 billion) worth of products crossing the border each day are taking no chances. At 11 p.m. Thursday, Brexit gets real.

Companies were already stockpiling and exploring alternatives to the crowded truck-ferry route across the English Channel when France unexpectedly closed its border for two days last week, citing a fast-moving Covid-19 outbreak in the U.K. The disruption produced miles-long backups at the Port of Dover — a warning shot for potential chaos as the Brexit transition period ends.

In response, logistics firms have redoubled efforts to relieve pressure on truck traffic, stepping up air freight, container ferry and air-cargo shipments. With the New Year arriving on a long weekend, concerns of an immediate repeat of last week’s spectacle have diminished. The port and its users will have the chance to ease into the new reality of a customs regime at the formerly open border.

“It should be quiet for at least the first few days,” said Richard Ballantyne, who heads the British Ports Association. “If there are blips of people turning up without the correct documentation, if it’s going to happen at any time, it’s better to be then.”

Dover remains the U.K.’s most important link with the EU, the country’s biggest trade partner. Still, the amount of tonnage has declined steadily since the year of the Brexit vote — down 14% from 2016 to 2019, Department for Transport data show. Other ports have meanwhile gained business: Liverpool’s traffic grew 7.6% and London Medway surged 43%.

Avoiding Dover

The unanswered question is what happens in the coming weeks and months. With Britain’s departure from the single market come a host of regulations and customs paperwork that threaten to gum up the free flow of trade and add costs for importers and exporters on both sides of the split.

The trend toward other ports and unaccompanied freight moving by train or ferry, along with supplemental air-cargo shipments of vital goods, is expected to continue into the new year, according to port officials and logistics firms.

Container volumes traveling between the port of Tilbury, on the River Thames east of London, and Zeebrugge, Belgium, have increased by a fifth in December as firms sought alternatives to the short straits. P&O Ferries Ltd. has added an additional ship to the route to cope with demand.

Charles Hammond, chief executive officer of Tilbury owner Forth Ports Ltd., credits the coronavirus pandemic with changing the logistics industry’s dynamics. Unaccompanied freight is “the answer to a number of the questions of our time,” he said.