â€˜Plan Bâ€™ is the name given to a set of social restrictions designed to limit the spread of coronavirus. Under the plan, work from home guidance has been reintroduced from Monday, but the new measures stop short of a full lockdown.
Announcing the introduction of new measures on Wednesday, Boris Johnson said: â€œThe best way to ensure we all have a Christmas as close to normal as possible is to get on with Plan B, irritating though it may be it is not a lockdown.â€
The news comes after the prime minister told ministers that the Omicron variant appears to be â€œmore transmissibleâ€ than the Delta strain. At his press conference, the prime minister warned it is clear the new strain is â€œgrowing much fasterâ€ than Delta, and cases of Omicron could be doubling every two or three days.
The social limitations will no doubt cause a stir, in a week where accusations of a No.10 Christmas party in December 2020 have dominated headlines.
The new rules will start to come into effect from Friday â€“ but not all the restrictions will come into force at at the same time. Hereâ€™s a summary of whatâ€™s changing in England.
Working from home
In recent months, many across England have enjoyed hybrid working, going into the office part-time after the official work from home mandate was scrapped. But from Monday, the advice is to work from home if you can once more.
Work from home guidance is already in place elsewhere in the UK and on Tuesday, Scotlandâ€™s first Minister Nicola Sturgeon said the guidance would continue until mid-January, warning that further coronavirus restrictions could not be ruled out.
Despite the return to working from home, Johnson said at the Downing Street briefing that Christmas parties and nativities could go ahead â€“ but urged people to â€œexercise due cautionâ€ and get their booster jabs.
He said: â€œWe donâ€™t want nativity plays to be cancelled, we think itâ€™s okay currently on what we can see to keep going with Christmas parties but obviously everybody should exercise due caution.â€
It comes after comments from health secretary Sajid Javid last week, urging people to go to their Christmas parties but to take a lateral flow test beforehand.
On December 1, he told Sky News: â€œI think people should continue to behave in the way they were planning to behave over Christmas. I donâ€™t think there is any need to change those plans.â€
Scotland, Wales and Northern Ireland have already introduced the use of vaccine passports for large venues, but ministers in England previously rejected plans.
Now, the NHS Covid pass, which can be obtained by having two vaccines or a negative lateral flow test, will be introduced for entry into nightclubs and other large venues from December 15.
Downing Street had already introduced mandatory face masks on public transport and in shops, bringing England in line with other UK nations. Face masks were also already mandatory in settings such as hairdressers, takeaways and estate agents.
Mandatory mask wearing will be extended to indoor public venues including cinemas, theatres and places of worship from Friday â€“ but face coverings will not be required in pubs and restaurants.
Earlier this month, the government introduced specific isolation rules for people who have been in contact with positive Omicron cases. Known contacts have to isolate for 10 days, even if they have been fully vaccinated. This remains the case.
On Tuesday December 7, new rules for international travel came into effect, requiring all travellers entering the UK to take a Covid-19 pre-departure test. If you test positive, you are not be allowed to travel.
The day before, Nigeria became the 11th country to go on the UKâ€™s red list for international travel, meaning anyone travelling from Nigeria would have to stay in a quarantine hotel upon arrive. All nations currently on that list are African.
The government did not announce any changes to travel in the latest press conference.