England and Scotland have reduced the number of people allowed to meet socially to six, amid a rise in coronavirus cases.
Wales is also cutting the numbers who can meet to six - but only indoors.
What are the new rules on socialising?
In England, the limit of up to six people from multiple households meeting up applies both indoors and outdoors, and to all ages.
So, gatherings in private homes, venues like pubs and restaurants, and in outdoor spaces like parks are all affected.
In Scotland, a maximum of six people from two households can meet. Unlike England, children under 12 - from those two households - will not be included in the total.
In Wales, it is now illegal for more than six people from an extended household to meet indoors. Children aged 11 and under from the extended household do not count in the total. Up to 30 people from different homes can still meet outside.
Northern Ireland has not announced any changes.
Will any social events of more than six be allowed?
Exceptions allowed in England include:
If your household or support bubble is larger than six Education and training settings Workplaces Protests and political events, if compliant with safety guidelines Jury duty or other legal commitments Children's play groups and youth clubs Support groups, such as for addiction or abuse Playing sport - either professionally or for funWeddings, funerals and special religious occasions can go ahead with up to 30 people attending, in groups of six or less. However, celebrations afterwards are limited to weddings or civil partnerships.
If you attend a protest, political event or other permitted outdoor event, you should attend in a group no larger than six. Although you might know others at the event, it is against the law to "mingle" with anyone outside your designated group.
Can I still go to the pub or to a place of worship?
Yes. Pubs, restaurants, shops and other venues will remain open, and there is no limit on how many can enter them, if they comply with safety rules and allow for social distancing.
However, each individual group can have no more than six people in it. Venues should also allow for social distancing between groups.
Similarly, places of worship can have as many people in them as is safe to do so. However, people can only attend in groups of six or less.
What are the rules for sports?
You can play organised indoor and outdoor sports in groups of more than six, if the sport's governing body has published safety guidance.
But if you play sports informally with people you don't live with, you must not play with more than six people.
So, for example, a Sunday League football match can still go ahead, but you can only have a kickabout in the park if six or less people take part.
Group exercise classes are also exempt from the rule of six, where they are being organised under Covid-secure guidelines.
Can I be fined for breaking the rules?
The new measures mean police can break up groups larger than six.
Members of the group can be fined if they fail to follow the rules. This will be £100 for a first offence, doubling on each further offence up to £3,200.
Image copyright Getty ImagesWhat is the guidance on social distancing?
Each UK nation is advising people to stay 2m (6ft) away from anyone they don't live with. However, there are some differences:
In England, if you can't stay 2m away, you can stay "1m plus" apart. The "plus" means doing something else to limit possible exposure - like wearing a face covering In Scotland, there are exemptions to the 2m rule in some places - like pubs and restaurants. Children aged 11 or under do not need to social distance In Wales, the 2m guidance reflects the fact it's not realistic to stay that far apart somewhere like a hairdresser's. Primary age children in Wales are also exempt Northern Ireland's guidance was 1m (3ft) for a time, but is now back at 2m Image copyright Getty ImagesWhat about shopping or public transport?
Face coverings are compulsory on public transport and in shops across the UK.
Some people are exempt, such as those with certain medical conditions and shop workers while on duty.
What if I get symptoms and have to self-isolate?
You should self-isolate by staying at home for 10 days and arrange to get tested.
The symptoms are:
new continuous cough high temperature loss of, or change in, your normal sense of taste or smellIf your test is positive, you must complete the remainder of your 10-day self-isolation. Anyone you live with should self isolate for 14 days (from the time you started having symptoms).
Contact tracers will also contact people with positive results.
Do I have to social distance myself from everyone?
Everyone except people you live with or, if you are in England, Scotland or Northern Ireland, anyone in your support bubble.
Single adults living alone or single parents with children under 18 can "bubble" with one other household of any size with no social distancing.
In Wales, you do not have to social distance if you are in an "extended household".
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