LONDON – A huge truck traffic jam in the port of Dover in England continued to ease on Saturday, days after France lifted a border blockade imposed over fears of a fast-spreading variant of the coronavirus that has already spread to Europe and Japan .

Up to 6,000 trucks had lined up at the height of the day-long traffic jam, and many drivers spent a bleak Christmas in their vehicles when France demanded that everyone crossing the border provide evidence of a negative coronavirus test.

“It was shocking to see things like this happening in a G7 country like Britain,” said Benjamin Richtzenhain, a traveler who crossed the Channel on Thursday. He said authorities had poor communication with those stuck in traffic and that access to water, bathrooms and blankets was restricted.

The misery in the harbor added to a general feeling of darkness that permeated the holiday season in the country. Christmas came barely a week after the government announced the presence of a rapidly spreading variant of coronavirus that swept the country and imposed widespread lockdowns and other severe restrictions.

A short-term Brexit deal with the European Union on Thursday meant the UK narrowly avoided getting out of the bloc without an agreement, but also brought home a sense of isolation. And dozen of countries have restricted travel from the UK in hopes of ruling out the new variant of the virus and disrupting plans during one of Europe’s biggest holidays.

Despite the new restrictions around the world, the virus variant has already spread to France, Spain and Japan. According to Japanese media, the Japanese government banned non-Japanese nationals from entering the country on Saturday to prevent the new tribe from spreading.

On Saturday morning, officials from the UK Transport Department said that since Wednesday when authorities prepared the tests, at least 1,600 vehicles had remained in traffic jams near the port, while at least 8,000 had crossed the English Channel via the Eurotunnel.

At the port, officials worked hard on Saturday to test the remaining drivers in hopes of deleting the backup. More than 15,526 were tested, 36 of which were positive, the department said.

Hundreds of other military personnel were deployed on Friday to step up testing efforts and distribute food and water provided by a number of organizations.

But almost a week after the blockades of the sea, rail and air routes, the scale of the task made it impossible to predict when the delays would improve and whether the drivers would spend another day in limbo and sleep another night in their trucks would.

Thousands of police officers, civilian testers, council planners and dock workers gave up their Christmas celebrations to reunite drivers with loved ones, said Grant Shapps, the UK’s transport secretary, who praised their efforts.

London airports were fairly quiet on Saturday and there were no signs of a rush the day after the United States imposed new restrictions on people flying in from the UK. From Monday, passengers to the United States will have to provide evidence of a negative coronavirus test.

A Heathrow Airport spokesman said Saturday is not expected to have a large number of travelers and that the day after Christmas is usually a quiet day of travel.