Video report by ITV News Political Correspondent Paul Brand
Households in London and the south-east England are to be banned from mixing over the festive period, while in the rest of the country, three households will be able to meet indoors on Christmas Day only, Boris Johnson has announced.
New Tier 4 restrictions have also been imposed on millions of people in London and the south-east of England. The tougher rules came into force at midnight on Sunday.
After the prime minister's statement, Wales' First Minister Mark Drakeford announced the country will go into a national lockdown from midnight and "Christmas bubbles" can only be formed on Christmas Day.
While Nicola Sturgeon announced a “strict travel ban” between Scotland and the rest of the UK and said all of the mainland would enter a lockdown from midnight on Boxing Day and last for three weeks.
Speaking alongside Chief Medical Officer Professor Chris Whitty and Chief Scientific Advisor Sir Patrick Vallance, Boris Johnson said the tightening of the restrictions is linked to the spread of a mutant variant of Covid-19 which scientists believe is spreading more quickly than the previous form.
This new variant is most prevalent in the south-east of England.
Explained: What are the new Covid-19 restrictions and which areas are in Tier 4?
Under the new tier 4 restrictions, a stay at home message has been put into law with exemptions for education, childcare and exercise.
All non-essential retail, indoor leisure, entertainment and beauty care (such as hairdressers and nail bars) will be forced to close.
Indoor hospitality, such as pubs, restaurants and cafes are already shut in these areas as they are in Tier 3.
The following areas will be under Tier 4:
Surrey (excluding Waverley)
The boroughs of Gosport, Havant, Portsmouth, Rother and Hastings
All 32 London boroughs and the City of London.
Essex (excluding Colchester, Uttlesford and Tendring)
The new rules for Tier 4 which came into force at midnight are:
People are advised not to enter Tier 4 areas and residents in tier must not stay overnight away from home
Travelling abroad is banned
You should work from home. Where you cannot, you are still able to travel to work
Non-essential shops will be shut
Indoor leisure such as gyms and swimming pools will be shut
Indoor entertainment such as cinemas and bowling alleys will be shut
Beauty services, such as hairdressers and nail bars will be shut
One person can meet with one person from another household outdoors
Mr Johnson did not confirm whether police would be told to stop people travelling home over the festive period or knock on doors on Christmas Day.
Support bubbles and childcare bubbles are exempt from the rules, and people are allowed outdoors for unlimited exercise.
The rules will be in place for two weeks and then will be reviewed.
Commenting on changes to Christmas rules, Mr Johnson said that as prime minster he believed there was “no alternative open to me”.
He said: “Without action the evidence suggests that infections would soar, hospitals would become overwhelmed and many thousands more would lose their lives.”
Mr Johnson added: “Yes, Christmas this year will be different, very different.
“We’re sacrificing the chance to see our loved ones this Christmas so that we have a better chance of protecting their loves, so that we can see them at future Christmases.
“And as sure as night follows day we will beat this virus, we’ll defeat it and reclaim our lives.”
He continued that he “bitterly regretted” the changes to the Christmas arrangements, but added they are "necessary".
"When the facts change you have to change your approach," the PM said.
“The briefing that I had yesterday about this mutation of the virus, particularly about the speed of transmission, was not possible to ignore.”
Prof Whitty said people considering leaving Tier 4 areas on Saturday ahead of the restrictions coming into force should unpack their bags and stay at home.
“My short answer would be ‘please unpack it at this stage’,” he said.
Prof Whitty told a Downing Street news conference: “If they were to go with this new variant, unwittingly, to an area that has a low prevalence and starts this being seeded even more outside the high prevalence areas that would be a significant risk to the area they went to.
“That is the reason we are really keen that people do not go from these areas.”
He indicated that Tier 3 and Tier 2 restrictions had proven ineffective at controlling the new variant.
If the new variant spread “none of them would be able to hold things with tier 3 and tier 2 elsewhere”.
The introduction of tier 4 and severe restrictions around Christmas come amid soaring coronavirus cases, particularly in London and south-east England where a new Covid variant has been identified.
Sir Patrick said that the new coronavirus variant may have originated in the UK, but that other types of variants around the world were likely.
“This (variant) is a particular constellation of changes, which we think is important,” he said.
“We think it may be in other countries as well, we think it is based mainly, there is a large outbreak in the UK, it may have started here we don’t know for sure.”
He added that global “surveillance” was needed to sequence the new variations.
ITV News Political Editor Robert Peston reacts to the latest Covid restrictions
On Saturday, a further 534 people died with 28 days of a coronavirus test while a further 27,052 people tested positive for coronavirus, bringing the UK total since the start of the pandemic to more than two million cases.
Mr Johnson said the new restrictions were necessary because of the spread of a variant coronavirus which was transmitting faster than the original.
The PM said the new variant may be up to 70% more transmissible and could increase the R value (the rate at which Covid spreads) by 0.4.
He told the briefing: “It seems that this spread is now being driven by the new variant of the virus that we spoke about earlier this week.
“Our advisers on the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag) have spent the last few days analysing this new variant – there’s no evidence that it causes more severe illness or higher mortality but it does appear to be passed on significantly more quickly."
On Friday, it was announced that the R rate had risen to between 1.1 and 1.2 across the country, meaning on average, 10 people with Covid will pass it on to 11 or 12 others, meaning the rate of the illness will increase exponentially.
Speaking during the Downing Street update, Prof Whitty highlighted the speed at which the new Covid variant is increasing: "This new variant not only moves fast - but it is beating all the other variants," he said.
Sir Patrick Vallance said that three questions needed to be asked about the new variant of coronavirus; whether it could be transmitted more readily, if it made people sicker, and whether it altered the immune response caused by vaccines.
He said the variant, which was thought to have emerged in mid-September in London or Kent, had a “significant substantial increase in transmissibility”.
Sir Patrick added that by December over 60% of infections in the capital had been the new variant, saying: “It moves fast and is becoming the dominant variant.”
Focusing on NHS data for the south-east and east of England and London, Sir Patrick said hospital admissions per day from September to now had gradually increased, with a “very sharp increase” during December.
“This virus has taken off, it’s moving fast and it’s leading inevitably to a sharp increase in hospital admissions,” he said.
Prof Whitty said there had been a “really dramatic increase in the proportion of cases” seen with the new variant.
Screening tests suggested that in south-east England, 43% of the virus was now the new variant, in the east of England it is 59% and in London 62%.
“Those have gone up very, very fast over the last few weeks,” he told a Downing Street news conference.
“This has really gone incredibly quickly. They are much lower in other areas of the country.”
The number of people in hospitals was also increasing in areas where the new variant was more prevalent.
“In the areas where this is very, very common you are seeing rates of increase of maybe 36% in the east of England, 34% in London and 28% in the south-east.
“These are the areas which have actually had significant numbers of this new variant.”
ITV News' Science Editor Tom Clarke on the new Covid-19 strain
Speaking earlier on Saturday, Chief Medical Officer Professor Chris Whitty said that while new Covid variant spreads "more quickly" than the type we have been living with for months, "there is no current evidence to suggest the new strain causes a higher mortality rate or that it affects vaccines and treatments" but further study would be needed to assess this.
At the Downing Street briefing, Prof Whitty said the new coronavirus variant would not decrease the effectiveness of current social distancing measures and that people must continue to follow them.
“Yes social distancing does work, it doesn’t work as a yes, no,” he told a press conference.
“The more things you do, the more determinedly you do them… the more this and every other respiratory virus goes down.
“It’s like you were cycling up a steep hill and now you’ve got the wind against you as well, you just have to do that much more to keep going.
“And that’s what we’re going to have to do… the actual tools have not changed.”
The Downing Street update came after Mr Johnson held a Cabinet meeting to discuss the impact of the new Covid strain.
He also spoke to Labour leader Sir Keir Starmer and the leaders of Wales, Northern Ireland and Scotland.
Mr Johnson also revealed 350,000 people in the UK have so far received their first dose of the Covid-19 vaccine.
Following the prime minister's urgent Covid press conference, Sir Keir Starmer said: We challenged the prime minister on Wednesday about this and he pushed back that challenge, and he told people to have a 'merry little Christmas'.
"Three days later he's ripping up their plans.
"Families will be heartbroken across the country as a result of this."
He added: "It's very important that whatever the rules are, everybody follows them.
"I say follow the government advice, whatever tier you're in, follow the rules. It's very important we all say that, the government and the opposition."
Criticism of the PM also came from within Tory ranks.
Mark Harper, the chair of the Covid Recovery Group of Conservative MPs which has been highly critical of the government’s strategy, called for Parliament be recalled so MPs could debate and vote on the changes.
“This is a very sad day. Lockdowns and increasingly severe tiered restrictions have failed in their goal of slowing the transmission of Covid," Mr Harper said.
“And now the government is expecting people to sacrifice the chance to share Christmas with family, friends and loved ones, just a few days after promising the opposite.
“If the government wants the support of the public and Parliament, it must publish a clear exit strategy from this nightmarish, cycle of damaging lockdowns and restrictions.
“More immediately, given the three-tier system and the initial Christmas household rules were expressly authorised by the House of Commons, these changes must also be put to a vote in the Commons at the earliest opportunity, even if that means a recall of the House.”