Boris Johnson has announced he is introducing Plan B COVID restrictions to curb infections and contain the spread of the Omicron variant.
Work-from-home guidance will return, vaccine passports will become mandatory in large venues and mask rules will be extended to combat the Omicron variant, the prime minister said.
He warned it was clear the new strain was “growing much faster” than Delta and cases could be doubling every two or three days.
Johnson told a press briefing in Downing Street the government would review whether to keep the new rules no later than January and before that if possible.
But he refused to give a fixed date and said it would be linked to how severe Omicron turned out to be and how effective these measures were in combating its spread.
He added it was okay to proceed with nativity plays and Christmas parties but everyone should “exercise due caution” by having ventilation, washing their hands and getting a COVID test before they went.
The UK reported 45,691 new cases of coronavirus on Tuesday. The seven-day rolling rate of new cases is 12.1% higher than this time last week.
A further 101 cases of Omicron were confirmed, bringing the UK total to 437.
Here is what Plan B means for you and your plans over the coming weeks
Vaccine passports for certain large-scale events
The NHS Covid pass is to be made mandatory in England for nightclubs and venues where large crowds gather in a week's time.
Johnson said: “We will also make the NHS COVID pass mandatory for entry into nightclubs and venues where large crowds gather, including unseated indoor venues with more than 500 people, unseated outdoor venues with more than 4,000 people and any venue with more than 10,000 people.
“The NHS COVID pass can still be obtained with two doses but we will keep this under review as the boosters roll out.
“And having taken clinical advice since the emergence of Omicron, a negative lateral flow test will also be sufficient.
“As we set out in Plan B, we will give businesses a week’s notice, so this will come into force in a week’s time, helping to keep these events and venues open at full capacity while giving everyone who attends them confidence that those around them have done the responsible thing to minimise risk to others.”
Mandatory face coverings in indoor settings
Johnson said rules around the wearing of face coverings would be “further extended”, as of Friday, to “most public indoor venues” including theatres and cinemas.
The prime minister added: “There will of course be exemptions where it is not practical, such as when eating, drinking, exercising or singing.”
Instructions to work from home if possible
Guidance to work from home is to be reintroduced in England as part of measures to halt the spread of the Omicron variant.
Watch: Bookings cancelled and plans changed as 'chilling talk of Plan B' hits hospitality sector
Some measures have already been introduced in order to try and contain the spread of Omicron, including mandatory face masks in shops and on public transport, and tighter restrictions and testing requirements for travellers.
Why is Plan B necessary?
The government has so far been adamant that there is no need to activate its Plan B.
However, the emergence and spread of Omicron has changed the picture, with Johnson telling the cabinet on Tuesday that “early indications were that it was more transmissible” than Delta.
A more infectious variant would require more stringent measures in order to keep hospitalisations at a level that can be sustained by the NHS.
The government has so far relied on vaccinations to stop the NHS being overwhelmed, and tighter rules could play a role in slowing the spread of the variant in order to allow more time for the booster jab vaccination campaign to progress.
The introduction of new restrictions would be a difficult move for the prime minister, who is under phenomenal pressure over allegations No 10 staff breached lockdown rules by holding a Christmas party last December.
Footage emerged on Tuesday night of senior aides joking about the party just days after it reportedly occurred in the run-up to Christmas 2020, casting doubt over Johnson's assertion that any event followed all COVID rules.
The PM's official spokesperson has denied multiple times that a party ever happened.
Watch: Starmer urges PM to 'be honest' about Tory Christmas party