A two-week “firebreak” lockdown will be introduced across Wales from 6pm on Friday, with everyone “required to stay at home”.
Here the PA news agency looks at how restrictions differ across the UK and Ireland.
A new three-tier system of coronavirus restrictions began last Wednesday.
Nationwide restrictions apply in Tier 1, which means people can meet in a group of up to six people from multiple households either indoors or outdoors, while pubs, bars and restaurants must close at 10pm.
Under the Tier 2 restrictions, people cannot meet with anyone they do not live with indoors unless they are part of a support bubble, while the rule of six applies for socialising outside.
Areas in Tier 2 currently include Greater Manchester, Cheshire, Derbyshire, West Yorkshire, South Yorkshire, Durham, Northumberland, Tyne and Wear, Tees Valley, West Midlands, Leicestershire and Nottinghamshire.
London, Essex, Elmbridge, Barrow-in-Furness, York, North East Derbyshire, Chesterfield and Erewash moved into Tier 2 on Saturday.
The most severe level of restrictions, Tier 3, means people cannot socialise with anyone outside their household in any indoor and many outdoor settings. Pubs and bars are forced to close unless they can operate as a restaurant.
Lancashire and the Liverpool City Region are the only two areas of England under Tier 3 restrictions, affecting 3.1 million people.
First Minister Mark Drakeford has confirmed a two-week “firebreak” lockdown is necessary to reduce the spread of coronavirus and prevent the NHS from becoming overwhelmed.
The “sharp and deep” lockdown will begin at 6pm on October 23 and last until November 9, with an instruction to “stay at home” harking back to the advice of the initial UK lockdown.
Mr Drakeford said the only exceptions will be critical workers and jobs where working from home is not possible.
All non-essential retail, leisure, hospitality and tourism businesses will close.
Community centres, libraries and recycling centres will also close, while places of worship will be shut other than for funerals or wedding ceremonies.
Childcare facilities will stay open, with primary and specialist schools reopening after the half-term break.
Secondary schools will also reopen after half-term but only for children in years seven and eight, though students taking exams will be able to attend for them.
– Northern Ireland
Tighter coronavirus restrictions announced by Stormont First Minister Arlene Foster came into force in Northern Ireland on Friday.
Pubs and restaurants have been closed for four weeks, with the exception of takeaways and deliveries, while schools are closed for two weeks – one of which will cover the half-term Halloween break.
Retail outlets will remain open, as will gyms for individual training.
Churches will also remain open and it is understood a 25-person limit will be placed on funerals and weddings, but wedding receptions are banned.
People should work from home unless unable to do so, and are urged not to take unnecessary journeys.
A tiering system is set to be introduced in Scotland, subject to the approval of Holyrood, replacing temporary coronavirus restrictions in place across the country.
It will indicate which level of regulations apply when the temporary restrictions end on October 25.
Pubs, bars, restaurants and cafes outside central Scotland can only conduct indoor business between 6am and 6pm and not serve alcohol, although alcoholic drinks can be served until 10pm in outdoor areas.
Pubs and licensed restaurants in five health board areas – Greater Glasgow and Clyde, Lanarkshire, Ayrshire and Arran, Lothian, and Forth Valley – have been forced to close for all but takeaway service until October 26.
Snooker and pool halls, indoor bowling, casinos and bingo halls have also been made to close and no outdoor live events are allowed in these five areas.
People cannot meet others from another household in indoor household settings across Scotland unless they are part of an “extended household”, available to people who live alone or only with children under 18.
People can meet outdoors in groups of up to six, not including children under 12, from no more than two households, and a maximum of six people from two households can meet in indoor hospitality settings, such as pubs and cafes.
Scots have been advised against travelling to high-risk areas of England, with Blackpool singled out as “associated with a large and growing number of Covid cases in Scotland”.
– Republic of Ireland
The Government is expected to sign off on plans to introduce country-wide restrictions amid a record number of cases in recent days.
The National Public Health Emergency Team (Nphet) has recommended moving to Level 5 of the Covid-19 restrictions framework for six weeks.
Counties Donegal, Cavan and Monaghan are currently at Level 4, while the rest of the country is at Level 3.
The Cabinet sub-committee was meeting on Monday before the full Cabinet meets later to sign off on new measures.
Level 5 restrictions would mean no household mixing and staying at home except to exercise within 5km.