Most of England has been placed in the top tier of Covid restrictions and the return of secondary schools delayed for two weeks as the new strain of the virus runs amok.
Three-quarters of the population of England will enter Tier 4 as Health Secretary Matt Hancock said the National Health Service was under "very significant pressure" amid reports several counties are on an emergency footing.
The Midlands, the North-East, parts of the North-West and parts of the South-West will move to Tier 4 which also bans multiple households from meeting each other indoors and outdoors.
"Nobody regrets these measures more bitterly than I do," said Boris Johnson at the Covid press briefing later on Wednesday.
In concert with the redrawn tiers map, UK secondary schools will also delay opening for two weeks to facilitate the roll-out of a mass testing regime for pupils.
Education Secretary Gavin Williamson told parliament that the exam-taking years 11 and 13 will now return on January 11 while other years will be back a week later on January 18.
Most primary schools will return as slated on January 4, however, although there will be exceptions in some Tier 4 areas where only the most vulnerable will return.
"We must always act swiftly when circumstances change," he said.
"The evidence about the new Covid variant and rising infection rates have required some immediate adjustment to our plans for the new term."
UK reports record number of daily Covid deaths
The dual announcements came on the same day the Oxford University/AstraZeneca vaccine was approved for use in the UK - a welcome bright spot on an otherwise gloomy landscape.
The UK government earlier reported a grim new record with 981 Covid deaths, beating the previous daily peak of 980 recorded on 10 April. It takes the total death toll to 72,548. Another 50,023 confirmed infections were also reported.
"There are over 21,000 people in hospital from Covid right now - we can see the impact this is having," Mr Hancock said. "The threat to life is real and the pressures on the NHS are real too."
He added: "Unfortunately, this new variant is spreading across the whole of England and cases are doubling fast."
Liverpool, which was previously singled out as a success story in getting cases down due to asymptomatic testing, will move up a band from Tier 2 to Tier 3.
The tightened restrictions will take effect from 12.01am on Thursday.
The remaining 25 per cent is all in Tier 3.
Mr Hancock resisted pressure from scientists and some politicians to place the entire country under the toughest restrictions despite Wednesday's record 53,135 new cases.
"Where it is possible to keep some of the freedoms we all cherish, I think we should. That is the basis of the tiered approach we are taking," he said.
Mr Johnson echoed the dilemma at the Covid press briefing later on Wednesday.
"We have to face the fact that we've got two big things happening at once in our fight against Covid - one's working for us and one's working against us.
"On the plus side we have got two valid vaccines, and we're racing to get them out - and on the bad side there is a new strain of the virus which is spreading much faster and surging across the country."
The UK prime minister was flanked at the briefing by analogy-loving deputy chief medical officer Jonathan Van-Tam and Professor Stephen Powis, the national medical director for England's NHS.
They both urged the public to play its part in curtailing the spread of the new variant with Prof Powis beseeching aspiring New Year revellers to "leave the parties for later in the year."