Prime Minister Boris Johnson urged people to stay at home for New Year amid a rapid rise in coronavirus infections.
During a briefing in Downing Street he appealed to those considering celebrating December 31 to follow the rules and see in 2021 safely at home.
Millions more people across England will be living under Tier 4 rules from midnight as the new variant of the virus spreads rapidly across the country.
Mr Johnsons said: “All of these measures in the end are designed to save lives and protect the NHS. For that very reason I must ask you to follow the rule where you live tomorrow night and see in the new year safely at home.
“That means not meeting up with friends or family indoors unless in the same household or support bubble and avoiding large gatherings of any kind
“We are still in the tunnel of this pandemic, the light however is not merely visible … the tunnel has been shortened, we’re moving faster through it and that gives me great confidence about the future in the spring.”
Professor Jonathan Van Tam, Deputy Chief Medical Officer for England, said: “Overall there has been considerable growth across the national footprint, particularly centred on London, the Home Counties and South Wales.
“This is now being reflected in the number of people going to hospital with Covid-19 across the UK.”
He added: “Unfortunately it is a pretty grim and depressing picture at the moment. The situation in the UK is precarious in many parts already, particularly in the South East in London.
“It is almost certainly true the NHS has not yet seen the impact of the infections that will have occurred during mixing on Christmas Day.
“I know New Year is coming up, it is normally a time of great festivity and enjoyment but you have just got to play your part in bringing us back from this very dangerous situation that we find ourselves in.”
Professor Stephen Powis, National Medical Director of NHS England, said: “We know it’s the end of the year, a time when people traditionally want to celebrate but it’s absolutely vital that people continue to follow the guidance by staying at home and not mixing.
“Mark the New Year with just nearest and dearest.
“Covid loves a crowd, so please leave the parties for later in the year.”