Prime Minister Boris Johnson has announced a second national lockdown for England to prevent a “medical and moral disaster” for the NHS.
Johnson said Christmas may be “very different” but he hoped taking action now would mean families can gather.
Pubs, restaurants, gyms and non-essential shops will have to close for four weeks from Thursday, he said.
But unlike the restrictions in spring, schools, colleges and universities can stay open.
After 2 December, the restrictions would be eased and regions would go back to the tiered system, he said.
Mr Johnson said: “Christmas is going to be different this year, perhaps very different, but it’s my sincere hope and belief that by taking tough action now we can allow families across the country to be together.”
The prime minister told a Downing Street news conference that he was “truly, truly sorry” for the impact on businesses, but said the furlough system paying 80% of employee wages will be extended through November.
“No responsible prime minister” could ignore figures which suggested deaths would reach “several thousand a day”, with a “peak of mortality” worse than the country saw in April, Mr Johnson said.
He said hospitals even in the south-west of England, where cases are among the lowest, will run out of capacity in weeks.
“Doctors and nurses would be forced to choose which patients to treat, who would get oxygen and who wouldn’t, who would live and who would die,” Mr Johnson said.
Mr Johnson, who chaired a cabinet meeting on Saturday afternoon, will make a statement to Parliament on Monday.
The UK recorded another 21,915 confirmed coronavirus cases on Saturday, bringing the total since the pandemic began to 1,011,660.
Another 326 people were reported to have died within 28 days of a positive test.
The UK is the ninth country to reach the milestone of a million cases – after the US, India, Brazil, Russia, France, Spain, Argentina and Colombia.
Meanwhile, Belgium is once again imposing strict lockdown measures in the face of rising Ccoronavirus infections, hospital admissions and deaths, announced Prime Minister Alexander De Croo during a press conference on Friday.
“Our country is in a state of sanitary emergency. The pressure is immense, as you have undoubtedly seen in recent days.
“At the moment, there is only one choice, and that is for all of us to support our healthcare sector as much as we can. We have to limit our physical contacts as much as possible,”said De Croo.
(BBC NEWS/Agencies reports)