At least 30 countries, including 17 in the neighboring European Union, have banned flights from the United Kingdom after the British government warned that a new variant of the coronavirus could be up to 70% more transmissible.

Why it matters: Supply chains are being disrupted just days before the U.K. is set to end the Brexit transition period without a free trade agreement with the EU — its largest and closest trading partner. A no-deal Brexit could cause massive damage to a British economy that’s already been ravaged by the pandemic.

Driving the news: U.K. Prime Minister Boris Johnson is set to hold an emergency meeting of advisers after France announced Sunday that it would close its borders for 48 hours, blocking off ports that account for roughly 20% of the U.K.’s trade in goods, according to AP.

  • The government has urged people not to travel to the county of Kent, which hosts many of the cross-channel ports used for access to the European continent and sees about 10,000 freight trucks a day through the Dover-Calais crossing.
  • European Union officials will meet Monday to discuss a coordinated response to the new coronavirus variant, which has been detected in Denmark, Italy and the Netherlands, according to the BBC.

Between the lines: There is thus far no evidence that the new variant of coronavirus is more deadly — only that it appears more transmissible. There is also no evidence that COVID-19 vaccines will be less effective against the new variant.

  • The discovery of the apparent increase in transmissibility forced Johnson to U-turn this weekend on a plan to soften coronavirus restrictions for five days to allow Brits to travel to see family and friends over Christmas.
  • Just days after Johnson said cancelling Christmas would be “inhuman,” the government ordered London and southeast England — where Health Secretary Matt Hancock has said the new variant is “getting out of control” — to enter into the strictest form of lockdown.

The big picture: The significant disruptions to travel and trade come less than two weeks before the end of the Brexit transition period on Dec. 31.

  • A no-deal Brexit with the EU, which negotiators now see as “very likely,” had already been expected to cause mass chaos at the ports that have now been blocked off due to coronavirus-related border closures.
  • Freight routes between England and France were already heavily congested due to pre-Brexit stockpiling by British companies. Images on Sunday showed trucks backed up for miles.
  • Critics of Johnson’s government have demanded that he ask for an extension to the transition period, fearing the dueling crises of a no-deal Brexit and an out-of-control pandemic could be catastrophic for the British economy. Johnson, who was elected on his promise to deliver Brexit, has consistently ruled out an extension.

Go deeper: U.K., EU brace for no-deal Brexit cliff as trade talks falter