Watch: Coronavirus restrictions explained
Local coronavirus lockdowns have been announced for Cardiff, Swansea and Llanelli, while Leeds is expected to face additional restrictions in a bid to curb the spread of the disease.
In Scotland, students have been banned from returning home and told not to go pubs after the country recorded its highest ever number of Covid-19 cases.
It comes as local restrictions are already in force across parts of the North West, North East, Midlands and West Yorkshire.
It means that around 15 million people in the UK are currently facing tighter coronavirus restrictions.
A raft of new national measures have been announced by Boris Johnson to curb the spread of Covid-19 in recent days, including the ‘rule of six’, closing hospitality venues at 10pm, increased use of mask wearing in public places and doubling fines for those breaking the rules to £200.
Here are the areas of the UK under local lockdowns, with details of what the rules are and how many people they impact.
The Welsh government announced from 6pm on Sunday, people will not be able to leave or enter Cardiff or Swansea without a reasonable excuse.
Under the restrictions, people will not be able to meet with anyone they do not live with, with extended households suspended. Anyone who is able to work from home to do so, the Welsh government added.
The town of Llanelli will go into local lockdown on Saturday at 6pm.
This is in additional to lockdown measures which are already in place in Bridgend, Blaenau Gwent, Merthyr Tydfil and Newport.
Health minister Vaughan Gething said there had been a “worrying and rapid rise” in cases of Covid-19 in the four areas.
Under the measures, which come into force at 6pm on Tuesday, people must not enter or leave the areas without a reasonable excuse.
Alongside Caerphilly and Rhondda Cynon Taf - where localised lockdown measures have already been introduced - it means nearly half of Wales is facing additional stricter rules.
People in Leeds will be banned from meeting with other households from midnight on Friday, the city council warned.
The new measures are expected to come into force at midnight on Friday, subject to a formal announcement by the government.
It joins Bradford, Kirklees and Calderdale as areas from which people are banned from socialising with other households or bubbles in private homes and gardens.
Some wards in these areas had previously been exempt from such restrictions but the government has confirmed they are now all bound by them.
London has been added to the coronavirus watchlist amid rising cases in the capital.
However, no additional measures are set to be enforced yet, while testing capacity in the city has been increased.
The Mayor of London, Sadiq Khan, pointed to a lack of testing capacity in the capital as the reason why it had become an area of concern.
He said: “London is at a very worrying tipping point right now. We’re seeing a sharp rise in 111 calls, hospital admissions and patients in ICU.
“The near collapse of test and trace and the resurgence of the virus means new measures to slow its spread were absolutely necessary."
Students in Scotland have been told they cannot return home to see their relatives and to avoid the pub this weekend after the country recorded its highest ever number of Covid-19 cases.
Students who flout the rules could be thrown out of university under the new rules.
It comes after around 120 students tested positive at Glasgow University and hundreds more have been self-isolating in various residences.
Earlier this week, first minister Nicola Sturgeon also rolled out a nationwide ban on people meeting in other households.
Members of different households can continue to meet in outdoors, including in gardens and hospitality settings.
Residents who have been in close contact with someone who has tested positive for Covid-19 should isolate for 14 days.
This quarantine extends to everyone in their household group.
Care home and hospital visits in the area have been limited to essential only, but outdoor visits to care homes are permitted by up to three individuals at a time from no more than two households.
Almost 2.2 million living in those areas are affected by the local restrictions.
North East England
Tougher coronavirus restrictions are in place in the North East of England.
Around 2 million people living in those areas will be subject to extra local restrictions as Covid-19 cases continue to rise.
The restrictions aimed at tackling the increase, will be enforced in Northumberland, North Tyneside, South Tyneside, Newcastle-upon-Tyne, Gateshead, Sunderland and County Durham.
People living in those areas will not be able to socialise with others outside their households or social bubbles.
Households in the City of Manchester, Trafford, Oldham, Bury, Bolton, Tameside, Salford and Rochdale are still under local lockdowns.
Almost 4.4 million people in total are affected by the tougher restrictions in those areas.
Meanwhile, restrictions in Wigan and Stockport have been eased, after cases in those areas decreased, to align with rates across the rest of the UK.
People in Bolton and Oldham must not mix with anyone from another household anywhere.
While a ban on households mixing indoors continues in City of Manchester, Salford, Rochdale, Trafford, Oldham, Bury and Tameside.
In Bolton, visits to hospitals and care homes will be also be restricted, while hospitality businesses in those areas have been subjected to takeaway services only.
Pubs and restaurants in Bolton have also been closed, bringing the town back in line with the national restrictions in place prior to July 4.
In addition, the following cannot reopen or resume in Bolton:
Indoor play areas - including soft play areas
Close contact services - including face treatments or make-up applications
Wedding receptions and celebrations involving more than 20 people
Wolverhampton, Oadby and Wigston
Residents will be banned from socialising with other people outside of their own households or support bubble in private homes and gardens from Tuesday 22 September.
Birmingham, Sandwell and Solihull
Tougher restrictions were introduced from Tuesday 15 September for households in Birmingham, Sandwell and Solihull as the Department of Health and Social Care announced a national intervention due to rising infections.
The measures affect around 1.6 million people living in Birmingham, Sandwell and Solihull.
Residents in those areas have been banned from meeting with people from outside their households or support bubble.
The seven-day rate for Birmingham to September 8 showed 78.2 cases per 100,000 with 892 cases over the period - among the highest in the city since April, according to NHS data.
Residents in the city of Leicester have been advised not to meet or host people from different households inside their homes or garden, unless they are in their support bubble.
They have also been banned from meeting people they do not live with in their homes or gardens, whether inside or outside of Leicester, unless they are in their support bubble.
Some businesses, including casinos, exhibition halls, bowling alleys, skating rinks and indoor play areas in the city were allowed to reopen from September 15, and they face the same restrictions as the rest of the country.
Individuals who are shielding in Leicester will no longer need to from 5 October.
North West England
Lockdown restrictions have come into force in Merseyside, Warrington, Halton, and Lancashire (excluding Blackpool and Greater Manchester) the government said.
Residents must not socialise with other people outside of their own households or support bubble in private homes and gardens, hospitality for food and drink will be restricted to table service only and late-night operating hours will be restricted, with leisure and entertainment venues including restaurants, pubs, and cinemas, required to close between 10pm and 5am.
A ban on two households mixing indoors will continue in Preston, Pendle and part of Blackburn, residents have also been advised not to visit someone else’s home or garden even if they live outside of the affected areas.
The tougher restrictions affect around 564,000 people living in those areas.
Restrictions have been eased to align with the rest of the country in Rossendale, Darwen East, Darwen South, Darwen West, Blackburn South East, Ewood, Livesey with Pleasington, and Mill Hill & Moorgate.
Residents in those areas should not socialise with people they don't live with in other indoor public venues, such as pubs, restaurants, cafes, shops, places of worship, community centres, leisure and entertainment venues, or visitor attractions.
They are allowed to visit those venues with people in their households or support bubble.
They have also been advised not to visit their loves ones in care homes other than in exceptional circumstances - while care homes should restrict visits to these circumstances.
Skate rinks, casinos, bowling alleys, close contact services, exhibition centres and conference halls, wedding receptions and celebrations for more than 20 people cannot reopen or resume.
In Blackburn, the following also must remain shut:
Indoor fitness and dance studios
Indoor sports courts and facilities
Indoor swimming pools, including indoor facilities at waterparks
Limits have been put in place on indoor and outdoor meetings following a rise in cases.
Lisburn and Castlereagh council area have now been added to the restrictions list, previously it was announced that the measures would apply to the Belfast council area, Ballymena, BT28, BT29 and BT43.
The number of people who can meet in groups outdoors is 15 - a decrease from the 30 that were previously permitted.
Indoor group meetings are now limited to six people, down from 10.
Northern Ireland has also put additional police enforcement in affected areas.