LONDON — Prime Minister Boris Johnson announced plans on Saturday to shut down pubs, restaurants and most retail shops throughout England, a stark reversal in the face of grim projections that the country could face a deadly winter from the coronavirus unless it takes draconian action.
Mr. Johnson presented the measures as part of a new tier of restrictions that will cover all of England. But the steps, which would take effect on Thursday and last until Dec. 2, amount to a nationwide lockdown — something Mr. Johnson resisted for weeks because of the damage he said it would do to the economy.
“We’ve got to be humble in the face of nature,” Mr. Johnson said at a hastily called news conference at 10 Downing Street. “In this county, alas, as across much of Europe, the virus is spreading even faster than the reasonable worst-case scenarios of our scientific advisers.”
The measures, announced after a tense day of meetings of Mr. Johnson’s cabinet, would bring England into line with France, Germany, Belgium, and Ireland, all of which have shut down large parts of their countries in recent days amid a rapid-fire resurgence in infections.
As in March, when the virus first engulfed Europe, England has been slower to respond than some of its European neighbors. That equivocation, critics say, has deepened the misery for the country, which has suffered one of Europe’s highest death tolls and heaviest economic blows from the pandemic.
Even as a second wave of infections swept in last month, Mr. Johnson was caught between a faction of his Conservative Party, which argued that another lockdown would devastate the economy, and his scientific advisers, who argued that it was unavoidable, given the exponential spread of the virus.
Under the current trajectory, the scientists said, hospitals would be stretched to capacity by the first week of December, even including the giant field hospitals that the government built, but never used, last spring.
Mr. Johnson had initially planned to roll out the new measures this coming Monday, but reports of the government’s deliberations leaked out on Friday evening, forcing the prime minister to move up his timetable.
“They have no choice,” said Devi Sridhar, head of the global public health program at the University of Edinburgh. “It’s better today than tomorrow, and it would have been better yesterday than today.”
The government said the measures would be voted on by Parliament next Wednesday, and there were indications that some Conservatives would try to block them. But with an 80-seat majority in Parliament and the support of the opposition Labour Party, there was little chance that these measures wouldn’t be adopted.
To cushion the economy from the worst effects of the lockdown, Mr. Johnson said the government would extend until December a wage-subsidy program for people whose jobs are threatened by the measures.
Under the plans, people would be required to stay at home unless their workplaces, such as factories or construction sites, need them. They would be allowed to go to school or college and leave home for a few other reasons, like buying food or seeking medical attention. But nonessential shops would be closed, people would be urged not to travel, except for business, and pubs and restaurants would only be allowed to serve take out food.
Scotland, Wales, and Northern Ireland have already instituted similar restrictions, leaving England as an outlier within the United Kingdom.
Until now, the prime minister’s approach had been to order targeted lockdowns in hot spots like the cities of Liverpool and Manchester, while allowing less affected places, like London, to operate more or less normally.
Mr. Johnson called this strategy a “stitch in time to save nine,” though it did not mollify the authorities in those hard-hit cities, whose leaders complained bitterly that the government was singling them out unfairly.
But the latest numbers suggest the tailored approach was no longer enough.
The government’s scientific advisory panel, known as SAGE, estimated in a report dated Oct. 14 that there were between 43,000 and 75,000 new infections a day in England, a rate that is above the worst-case scenarios calculated only weeks before that. The virus has spread beyond the initial hot spots in the north of England.
Hospital admissions are also running ahead of the worst-case scenario, the panel said, raising the specter that within weeks, the National Health Service will not be able to cope with the influx of patients. That could drive Britain’s virus-related death toll beyond the 85,000 that scientists estimated could be reached this winter.
On Saturday, Britain reported 21,915 new infections, passing a grim milestone of one million people who have tested positive. It admitted 1,444 patients to the hospital with symptoms of Covid-19, the disease caused by the virus. Nearly 1,000 patients are in intensive care units, while 326 people died on Saturday alone.
Britain’s total death toll from the virus is 58,925, one of the highest in Europe.
For weeks, politics has colored the debate over how to curb the virus. The leader of the opposition Labour Party, Keir Starmer, called on Mr. Johnson in mid-October to impose a two-week lockdown that scientists said would act as a “circuit breaker” on the chain of transmissions. He cited a report from SAGE that warned Britain faced a “very large epidemic with catastrophic consequences.”
Mr. Johnson accused Mr. Starmer of failing to take into account the economic fallout from such a lockdown, which has led influential cabinet ministers, including the chancellor of the Exchequer, Rishi Sunak, to raise alarms.
Imposing the lockdown now, analysts said, could hurt Mr. Johnson within his party because it will look like he is buckling to pressure from the opposition. But polls indicate that the British public is more sympathetic.
Locking down the economy in November is also a way to salvage Christmas. By cutting the transmission rate, the government could relax restrictions in December to allow families and friends to celebrate together.
British papers have been full of headlines about whether Mr. Johnson will “cancel Christmas.” He has insisted that he wants university students to be reunited with their families during the holidays.
While medical experts generally applauded the planned lockdown, some questioned why the government did not act sooner, like during the midterm school break, which began earlier this month, as public health experts proposed.
Others said the government still had not fixed its test-and-trace system, which continues to fall far short of its goals. Until it does that, experts said, Britain would not be able to identify or break the chains of transmission — setting the stage for further outbreaks after the lockdown is lifted.
“You use lockdowns to build up test and tracing,” Ms. Sridhar said. “We will be stuck in these cycles of lockdown and release until they decide we can’t live with this virus because it’s killing our economy.”