UPDATE: Omicron and latest rules
Omicron: What are the new Covid rules for the UK?
What are the changes to rules and restrictions in UK
Self Isolation - Close contacts
From Tuesday, 14 December in England, people who are double-vaccinated and come into contact with a person with Covid (all variants) should take daily lateral flow tests for seven days, rather than immediately self-isolating.
Anyone who tests positive will then need to self-isolate and take a PCR test to verify the result. If the PCR is positive, they must self-isolate for 10 days from the day they took the positive rapid test or developed symptoms.
This only applies to the double-jabbed, and anyone in England who is unvaccinated still needs to isolate if they are a contact of a positive Covid case.
Scotland has announced people should isolate for 10 days if anyone in their household tests positive for Covid. This is regardless of their vaccination status, or a recent negative test.
Anyone in close contact with someone who tests positive for Covid, but who is not in their household, should isolate and take a PCR test. If the test is negative, they can leave isolation - if they are double-vaccinated.
Across the rest of the UK, anyone who lives with - or is identified as a contact of a suspected or confirmed Omicron case - must self-isolate for 10 days. This applies whatever a person's age and includes people who are fully vaccinated.
Suspected or confirmed Omicron cases are identified through PCR tests. Although confirming Omicron can take a couple of weeks, the initial positive test result will indicate if you are suspected of having it.
What other self-isolation requirements are there?
You also need to self-isolate for 10 days if you:
test positive or have Covid symptoms
are waiting for the results of a PCR test after developing Covid symptoms
are an adult who has not been fully vaccinated, who lives with someone who tests positive (or who has Covid symptoms)
are an adult who has not been fully vaccinated, who has been identified by contact tracers as a close contact of someone who has tested positive
People in Wales are also asked to self-isolate and get tested if someone from their household shows Covid symptoms or tests positive.
Under-18s don't have to self-isolate after contact with a positive case, even if they are not vaccinated, although they are advised to take a PCR test.
If you are "pinged" by the NHS Covid App to say that you've been in close proximity to someone who subsequently tested positive for Covid, you will only be advised to self-isolate if you are 18 or over and not fully vaccinated.
Production Protocols
Where you are working on a production, you must also follow the production COVID protocol and risk assessment. The testing and isolation requirements may be greater than the measures above, in particular where close contact cohorts are in place. The mitigation and control measures in your protocols will potentially be greater than the minimum outlined advice for general public and work places.
What are the latest rules in England
Face coverings are now compulsory in most indoor public venues, including theatres and cinemas - as well as on public transport and in places like shops and hairdressers. Masks won't be needed in pubs or restaurants, or venues like gyms where it's "not practical".
People should work from home "if they can", from Monday 13 December.
NHS Covid Passes - or a recent negative lateral flow test - will be needed to enter some venues from Wednesday 15 December, if approved by MPs.
People will need to demonstrate their Covid status to gain entry to:
Nightclubs
Indoor unseated venues with more than 500 people
Unseated outdoor venues with more than 4,000 people
Any venue with more than 10,000 people
Lateral flow tests should be used before people enter "a high-risk setting", such as a crowded place, the government says.
Self-isolation for contacts of Covid cases applies for 10 days to those who are unvaccinated, test positive or develop symptoms, from Tuesday. Daily lateral flow testing will also replace self-isolation for double jabbed contacts. Self-isolation will only apply if a test is positive.
Other rules include:
Pupils at secondary schools are "strongly advised" to wear face coverings in communal areas; as should staff and visitors at all schools and childcare settings
Anyone travelling to the UK has to take a PCR or lateral flow test no more than 48 hours before their departure, and a PCR test within 48 hours of arrival in the UK, self-isolating until they have a negative result
1m-plus social distancing remains in places including hospitals and passport control
Anyone with Covid symptoms, or who tests positive, must self-isolate
What are the latest rules in Scotland
Scotland First Minister Nicola Sturgeon has announced changes to deal with the Omicron variant:
From Saturday 11 December, people should isolate for 10 days - regardless vaccination status or a negative test - if anyone in their household tests positive for Covid
If you've been in close contact with someone NOT in your household who's tested positive, you should isolate and take a PCR test. If it's negative, and you are double-vaccinated, you can leave isolation
People should think about postponing Christmas parties
Other restrictions already in place include:
2m (6ft) physical distancing rules remain in healthcare settings such as hospitals, GP surgeries and dentists
face coverings still compulsory on public transport and inside places like shops
all school staff and secondary pupils to wear face coverings indoors
indoor hospitality venues must collect customer contact details
work from home where possible until at least the middle of January
all over-18s required to prove their vaccine status at nightclubs and other venues
First Minister Nicola Sturgeon has urged people to take LFTs before mixing with other households
What are the latest rules in Wales
People are being urged to take lateral flow tests before going out - for example, shopping, or visiting others.
They are also now being asked to wear masks in pubs and restaurants when not eating or drinking.
The Welsh government has said Covid rules will now be reviewed weekly, rather than every three weeks.
Existing restrictions include:
NHS Covid Pass needed for entry to nightclubs, cinemas, theatres and concert halls and many other indoor and outdoor events
working from home wherever possible
compulsory face coverings in schools, on public transport, and in shops and hospitals
What are the latest rules in Northern Ireland
Restrictions include:
a limit of 30 people from different households mixing in homes
face coverings compulsory in shops, indoor seated venues and visitor attractions, public transport and some other settings
post-primary pupils must wear a face covering inside school buildings, as well as on school transport. Staff are encouraged to wear masks in school areas where they can't socially distance
vaccine passports for venues including nightclubs, bars and cinemas
work from home wherever possible