UK Prime Minister Boris Johnson warned Britain was in a "tough final stretch, made only tougher by the new variant" as he said England's lockdown could stay in place until the end of March amid soaring COVID-19 infections.
He said the mutant strain of the virus identified in London and the southeast last month was spreading with "frightening ease and speed" and worsening a death toll that stood at 76,305 in Tuesday's official figures.
That tally only includes deaths that took place within 28 days of a first positive coronavirus test. Figures released on Wednesday by the Office For National Statistics (ONS), which include anyone with the COVID on the death certificate, suggest the real toll is higher than 90,000.
"After the marathon of last year we are indeed now in a sprint, a race to vaccinate the vulnerable faster than the virus can reach them," said Mr Johnson in parliament, where MPs were recalled to vote retrospectively on the lockdown that is now in effect across England.
Outside, anti-lockdown protesters were arrested in Parliament Square as tempers frayed over the harsh new measures that will see residents unable to leave their homes except for essential reasons such as once-daily exercise and food shopping.
But Johnson stressed that the country's strictest lockdown since March last year was unavoidable as the situation were changing.
"It is inescapable that the facts are changing, and we must change our response," the prime minister said, as people were told to stay at home and schools were shuttered. The opposition have indicated they will support the lockdown.
The UK has one of the highest death tolls in the world, and has now tallied almost 2.8 million infections. It reported 60,916 new cases on Tuesday, its highest ever daily total, as Scotland also entered a national lockdown.
A quarter of all deaths registered in the week to Christmas were COVID-related — a figure 44.8% above the five-year average.
Education Secretary Gavin Williamson earlier confirmed that key GCSE and A-Level exams were cancelled and school students would be assessed by their teachers instead.
Local elections due in May are "under review" after they were postponed once already last year, Johnson said.
RACE FOR A VACCINE
England's lockdown measures will be reviewed in mid-February but it is clear the UK is in a dire situation as the virus runs rampant once more, propelled by the highly contagious new variant.
One in 50 people in England and one in 30 in London were estimated to have had the virus last week, according to the ONS.
The number of people in hospital is now 40 per cent higher than at the April peak last year.
The UK government is placing all its hopes on distributing vaccines to the most vulnerable groups at unprecedented speed. Since the programme began a month ago, more than 1.3 million people have received a first vaccine dose in the UK, with the National Health Service delaying follow-up doses in order to spread as much protection as many people as possible.
But the speed of vaccinations will need to be dramatically ramped to two million people per week from now in order to ensure that most of the extremely vulnerable population is covered by March.
The UK was the first country to start rolling out vaccines early last month with the Pfizer/BioNTech shot, and this week began injections of the Oxford University/AstraZeneca jab, which does not need to be stored at such low temperatures.
UK Labour leader Keir Starmer said Johnson should also impose mandatory pre-flight testing for airline passengers coming to Britain, after other mutant strains emerged in South Africa and Denmark.