People should avoid unnecessary contact and stick to lockdown rules, England's chief medical officer Prof Chris Whitty has said. The surge in coronavirus cases "is everybody's problem", he argued.
England, Northern Ireland, Scotland and Wales have all introduced lockdowns.
How long will the lockdowns last?
- Scotland's lockdown will continue until mid-February at the earliest, First Minister Nicola Sturgeon has announced
- England's lockdown laws end on 31 March, but Prime Minister Boris Johnson has said it is "too early" to know whether it will be possible to lift restrictions in the spring
- In Wales, the lockdown will be reviewed at the end of January, but the government has previously said it does not see "much headroom for change"
- Northern Ireland's lockdown has been extended until 5 March
What are England's lockdown rules?
People in England must stay at home and only go out for "a reasonable excuse".
You are not allowed to leave home to meet people socially if you don't live together, or have a support bubble with them.
A new £800 fine for attending house parties of more than 15 people has been announced. It will double for each additional offence - up to £6,400. Organisers will be fined £10,000.
What's a "reasonable excuse" for leaving home?
- Shopping for essentials such as food and medicine
- Meeting your support or childcare bubble
- Children can move between separated parents
- Working where it is "unreasonable" to work from home, for example nannies, cleaners and tradespeople
- Education, training, childcare, medical appointments and emergencies
- Religious worship
- Moving house
You can exercise with one person from another household in an open public space. You should stay two metres apart from each other.
If you do leave home for one of these reasons, you should stay local - unless it is necessary to go further, for example to go to work.
Travel - internationally or around the UK - is only allowed if it is essential.
If you are clinically extremely vulnerable you should only go out for medical appointments, exercise or if it is essential. You should not attend work.
Pubs and restaurants and non-essential shops have closed, as have indoor and outdoor sports facilities including gyms and tennis courts.
Essential businesses and services can stay open - including:
- Supermarkets, food shops, pharmacies and garden centres
- Places of worship
- Petrol stations and MOT services
- Banks and post offices
- Doctors and dentists' surgeries and vets
- Car parks, public toilets and playgrounds
What are the restrictions in Scotland?
Scotland has its own restriction levels - from zero to four.
Mainland Scotland (and the isles of Skye, Arran, Bute, Gigha, Barra and Vatersay) have moved to "enhanced level four".
All other island communities remain in level three.
"Enhanced" level four rules
- Schools closed to all but vulnerable pupils and the children of key workers
- People should only leave home for essential reasons such as caring responsibilities, essential shopping, or exercise
- Anyone shielding should not go into work, even if they cannot work from home
- Two people from up to two households can meet outdoors (under-11s are not included in the limit and can play together outside)
- Places of worship closed except for weddings (up to five people) and funeral services (up to 20 people) - wakes not allowed
- No travelling outside your own local authority area for anything other than "essential" reasons
- No travel between Scotland and other parts of the UK unless the journey is essential
- Only shops selling essential items - such as clothing, footwear and baby equipment - allowed to offer click and collect
- Customers not allowed to collect takeaways from inside restaurants, or drink alcohol outdoors in public
Level three (very high) rules
- Pubs and restaurants open until 18:00, but no alcohol
- Leisure and entertainment venues closed
- Non-essential travel in or out of the area not allowed
- Indoor gym use restricted to individuals
- Hairdressers and barbers can open
Levels two, one and zero
None of these levels currently apply to any area in Scotland.
What are Northern Ireland's rules?
The current rules include:
- Closure of all non-essential shops, including garden centres and homeware stores
- No click-and-collect services, apart from supermarkets
- Closure of hair and beauty salons
- Hospitality businesses open only for takeaway and delivery
- Leisure and entertainment venues must close
- Off-licences must close by 20:00
- Weddings, civil partnership ceremonies and funerals limited to 25 people - wedding receptions not allowed
- Churches can open for communal service (this is under review)
- Elite sport allowed behind closed doors
What are the rules in Wales?
Wales is in a national lockdown at alert level four.
- You must stay at home, except for very limited purposes
- You must not visit other households, or meet other people you do not live with, unless they are in your support bubble
- Wedding receptions and wakes are not allowed
- Work from home if you can
- No travel without reasonable excuse
The following must close:
- Entertainment venues including theatres and concert halls
- Indoor and outdoor visitor attractions
- Sport, leisure and fitness facilities
- Pubs, bars and cafes (except for takeaway and delivery)
- Hairdressers and nail salons
- Non-essential shops (click and collect allowed)
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