Boris Johnson orders a severe lockdown, saying a more infectious variant of the virus is ripping through Britain.

https://www.nytimes.com/live/2020/12/19/world/covid-19-coronavirus#boris-johnson-orders-a-severe-lockdown-saying-a-more-infectious-variant-of-the-virus-is-ripping-through-britain

LONDON — Alarmed by what he called a faster-spreading variant of the coronavirus, Prime Minister Boris Johnson abruptly reversed course on Saturday and imposed a wholesale lockdown on London and most of England’s southeast.

The decision, which Mr. Johnson announced after an emergency meeting of his cabinet, came after the government got new evidence of a variant first detected several weeks ago in Kent, southeast of London, which the prime minister asserted was 70 percent more transmissible than previous versions. Cabinet ministers were told that in London, cases had nearly doubled in the last week, with the new variant accounting for 60 percent of those.

The new measures, which take effect at the end of Saturday night, are designed, in effect, to cut off the capital and its surrounding counties from the rest of England. They are the most severe measures the government has taken since it imposed a lockdown on the country in March, and they reflect a fear that the new variant could supercharge the transmission of the virus as winter takes hold.

“When the virus changes its method of attack, we must change our method of defense,” a somber Mr. Johnson said at a news conference. “We have to act on information as we have it, because this is now spreading very fast.”

Viral mutations are not usual, and this variant — known as VUI 202012/01 — has been detected in a handful of other countries, but medical experts expressed alarm about its apparent infectiousness. British ministers have been told that there is no evidence that the new variant is inherently more dangerous, or that it is more resistant to vaccines than others.

Its infectiousness, however, raises the prospect of accelerating infections, leading to more hospitalizations and deaths. The British government said it had notified the World Health Organization about the prevalence of the new variant. ...