NEW YORK (NYTIMES) - Countries across Europe and beyond began closing their borders to travellers from the United Kingdom on Sunday (Dec 20), and the European Union set up a crisis management meeting, a day after Britain's Prime Minister Boris Johnson ordered a wholesale lockdown on London and surrounding areas, citing concerns of a new fast-spreading variant of the coronavirus.

Train stations in London last Saturday night filled with crowds of people scrambling to leave the city to escape the new restrictions, which went into effect at midnight and effectively quarantined the capital and other areas from the rest of the country, the harshest measures to be taken since the country's first lockdown in March.

On Sunday, Britain's health secretary, Mr Matt Hancock, called those who packed trains "clearly irresponsible". He also said that the restrictions Mr Johnson imposed could be in place for months.

The first wave of countries to bar travellers from Britain were in Europe. The Netherlands said it would suspend flights from Britain from Sunday until Jan 1, noting that the variant found in England was "thought to spread more easily and more quickly".

Italy also suspended air travel from Britain, and Belgian officials on Sunday enacted a 24-hour ban on arrivals from the country by air or train, which could be extended. Germany and Switzerland both announced bans on travel from Britain and South Africa, where a similarly contagious version of the virus has emerged.

Austria, Ireland, France and Bulgaria also announced bans. Portugal, which banned travel to and from Britain, is making exceptions for Portuguese nationals or residents. And Canada said on Sunday that it would ban all flights from Britain for 72 hours, beginning at midnight.

In the United States, Governor Andrew Cuomo of New York urged the federal government to take action, saying that "right now, this variant in the UK is getting on a place and flying to JFK", while also acknowledging that it may be too late. The Department of State said that its travel advisory to Britain had not been changed and remained at Level 3.

Spain asked the EU for a coordinated response, and senior officials from the bloc's 27 member states met by video conference on Sunday evening to share their plans. They agreed to decide on any coordinated action at the crisis management meeting, to be held on Monday morning.

Within hours, more countries took action. Iran suspended flights to Britain for two weeks, Reuters reported. Israel barred foreign nationals not only from Britain, but also from South Africa and Denmark, where a coronavirus mutation that occurred in minks was transmitted back into the human population.

Turkey temporarily suspended flights from those three countries, as well as the Netherlands, Reuters said.

Transportation officials in England said they would increase the number of police officers monitoring hubs like railway stations to ensure only essential journeys were being taken. And during one of the year's biggest shipping periods, the effects were sure to be seen at Britain's ports.

The Port of Dover, one of the world's busiest, where thousands of trucks travel each day, closed its ferry terminal to "all accompanied traffic". Traffic had reached a fever pitch as companies stockpiled goods before new post-Brexit customs rules go into effect.

Viral mutations are not uncommon, and British officials said this variant had been detected in a handful of other countries.

The estimate of greater transmissibility for the British variant is based on modelling and has not been confirmed by lab experiments, said Dr Muge Cevik, an infectious disease expert at the University of St Andrews in Scotland and a scientific adviser to the British government.

"Overall, I think we need to have a little bit more experimental data," she said. "We can't entirely rule out the fact that some of this transmissibility data might be related to human behaviour."

The virus crisis came as another down-to-the-wire drama is playing out for Britons: the trade negotiations between Britain and the EU. Critics say the British Prime Minister's penchant for last-minute decisions has complicated the handling of the coronavirus and narrowed the window for scrutiny of any trade deal with the EU.