British Prime Minister Boris Johnson is poised to announce even tougher coronavirus restrictions within hours and the UK Parliament is being urgently recalled, as the country struggles to curb the spread of a new, more infectious strain of the disease.
"The spread of the new variant of Covid-19 has led to rapidly escalating case numbers across the country," a spokesman for 10 Downing Street told Sky News UK.
"The Prime Minister is clear that further steps must now be taken to arrest this rise and to protect the National Health Service and save lives.
"He will set those out this evening."
Johnson is expected to address the British public at 8pm local time (9am NZT). Parliament will sit on Wednesday.
He may follow the lead of Scotland's First Minister Nicola Sturgeon, who has ordered Scots into a full lockdown from midnight due to a "steeply rising trend of infections".
As things stand, everyone in the UK is living under either Tier 3 or Tier 4 restrictions.
The stricter set of rules applies to about three-quarters of England, including all of London and swaths of the country's southeast.
Residents in Tier 4 regions are unable to leave home or their local area unless they have a "reasonable excuse", and cannot hold indoor gatherings with anyone outside their own support bubble.
Non-essential retail shops, indoor entertainment venues, gyms and beauty services have been shut. Weddings and civil partnership ceremonies are also prohibited.
In Tier 3 areas, delivery and takeaway services are allowed, as are outdoor gatherings of up to six people and small wedding ceremonies (but not receptions).
Shops, gyms and personal care services are also still open.
Johnson foreshadowed a potential tightening of the restrictions during an interview with the BBC yesterday.
"There are obviously a range of tougher measures that we would have to consider," he said.
"I'm not going to speculate now about what they would be."
The context for all this is a deeply troubling spike in cases, the vast majority of which are the mutated, more infectious version of Covid-19.
The UK recorded a further 54,990 cases yesterday. It didn't quite reach the daily record of 57,725, recorded on January 2, but it marked the sixth consecutive day above the 50,000 threshold.
Total cases have now reached 2,654,779, with 74,570 deaths.
The scale of the problem is laid out in stark detail by a new graph from the Oxford University initiative Our World in Data.
Shared on Twitter by University College London's Associate Professor in Global Politics Brian Klass, the startling graphic shows transmissions of the virus between December 2020 and January 2021.
A near-vertical line represents the country's current spike, with cases jumping from roughly 15,000 a day to over 57,000 in the space of a month between December and January.
"With the new, more transmissible variant, this chart of daily new cases of covid in the UK is terrifying," said Klass.
"It's basically a vertical line at this point."
The number of deaths linked to the new variant has also grown, with 445 and 454 reported on Friday and Saturday respectively, doubling the low-200s figures from a week ago.
There has been talk of a potential Tier 5 lockdown looming for days now.
According to the Independent, this could involve the complete closure of sport facilities, with weddings and funerals also prohibited.
People might also be banned from leaving their homes, unless they're buying groceries or essential supplies, providing care, accessing emergency services or pursuing exercise.
While the UK's current outlook is obviously bleak, there is at least a small sliver of hope.
Johnson has called for the accelerated rollout of a vaccine, ordering a total of 100 million units of the Oxford/AstraZeneca jab. By Monday local time, 530,000 doses will be ready to be administered, with tens of millions more doses on the way.
Even that relatively good news, however, comes with concerns.
The Government's rollout involves delaying the second dose of Pfizer's vaccine until 12 weeks after the first dose, instead of the three week-delay tested in clinical trials. Experts have warned it is unclear how effective the second dose will be under that plan.
Professor Anthony Harnden, deputy chairman of Britain's Joint Committee on Vaccination and Immunisation, has argued that the first dose provides "90 per cent protection" and the priority is to get "as many people vaccinated in the elderly and vulnerable community as possible".
"We are in a dire situation in this country at the moment. The virus is rapidly spreading and the more vaccine we can get into these priority groups that we've identified, the more deaths and hospitalisations we will prevent," he told the BBC.
More than a million people in Britain have been vaccinated so far.