Boris Johnson has announced a new lockdown for England that will last until at least mid-February as the country reels from a faster-spreading new version of the coronavirus.
Britain's prime minister said that the restrictions will require people to stay at home and primary and secondary schools to close alongside all non-essential shops.
University students will not return to campus and restaurants will only be permitted to provide take-out services.
Johnson said that the measures were necessary to avoid the UK's health service from being overwhelmed, as the country sees a surge of cases of the deadly virus.
“As I speak to you tonight, our hospitals are under more pressure from COVID than at any time since the start of the pandemic,” he said.
"I know how tough this is. I know how frustrated you are. Now more than ever we must pull together."
It comes as Britain announces a record 58,784 new cases of coronavirus and 407 deaths as the spread of the virus raises fears of a tough new lockdown across the nation.
In a statement, Yvonne Doyle, medical director for Public Health England, said that the "continuous rise" in cases should be a "bitter warning for us all".
"We must not forget the basics - the lives of our friends and family depend on it," she said.
"Keep your distance from others, wash your hands, and wear a mask. This virus will transmit wherever you let your guard down."
British opposition leader Sir Keir Starmer earlier also called for a full, nationwide lockdown, claiming that the government's tier system - under which the UK is split into four tiers with stricter restrictions in each depending on the spread of the virus - was not working.
"The virus is out of control and we know that the tier system isn't working. I know that, the prime minister knows that, and therefore tougher national restrictions are inevitable," Starmer said.
In recent weeks, Britain's government has been criticised for failing to impose restrictions on those entering the UK, including - as in other European countries - a requirement for new arrivals to provide a negative test before they are allowed entry.
But Johnson is also under fire from those within in his own party and the public who are opposed to greater restrictions on movement or a stricter lockdown.
Meanwhile, Scotland will go into another coronavirus lockdown from midnight tonight until the end of January, Nicola Sturgeon has announced.
The Scottish first minister revealed the latest measures to parliament on Monday as she said she felt "more concern" over the current COVID-19 situation compared with the first peak in March.