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The government has warned of "tougher measures" if people do not follow the latest coronavirus restrictions.
In a television broadcast on Tuesday night, Prime Minister Boris Johnson said "we must reserve the right to go further" if cases continue to rise.
Tighter restrictions were announced in all four UK nations. Mr Johnson warned they could last up to six months.
In England, people are being told to work from home if they can and rules on face coverings have been expanded.
Pubs, restaurants and other hospitality venues will have to close by 22:00 BST, and the number of people allowed at weddings has been halved.
Meanwhile, the fines for breaking the rules will also increase to £200 on the first offence.
Hospitality venues will also have to close early in Scotland and Wales - but Scotland has gone further, banning people from visiting other people's homes from Wednesday. Northern Ireland has also already banned households mixing indoors.
The government's chief medical adviser, Prof Chris Whitty, is understood to believe it is inevitable England will to have to follow Scotland's latest move, according to the Times.
Conservative MPs also expect limits on visits to households to be "the next step", according to Nicholas Watt, political editor of the BBC's Newsnight.
"They don't like it but they could probably live with it," he said, though he added that if the government went further with restrictions on the hospitality sector "that would really create insurrection on the Tory benches".
Mr Johnson will face further scrutiny from MPs in the House of Commons later during Prime Minister's Questions.
Defending the latest strategy, Foreign Secretary Dominic Raab said there was no "one silver bullet" but the range of measures introduced in England were "balanced, proportionate and targeted".
"Overwhelmingly the public have responded every time but increasingly there's been a small minority where compliance has frayed," he added.
He told BBC's Breakfast that if people follow all the measures - and no one thinks they are immune - "we will get through this and we will get to Christmas not in a national lockdown".
Mr Johnson's warning that stricter measures could follow comes six months after the UK's coronavirus lockdown - first announced on the 23 March - which saw strict curbs on life to tackle the spread of the virus.
People were told to only leave home for one of four reasons, including shopping for food and medicine, exercise, medical needs, and travelling to and from work "where absolutely necessary".
'Too many breaches'
In his pre-recorded address from Downing Street, Mr Johnson said he was "spiritually reluctant" to infringe on people's freedoms, "but unless we take action the risk is that we will have to go for tougher measures later, when the deaths have already mounted".
He added that while the vast majority have complied with the measures so far, "there have been too many breaches".
Former Labour home secretary Alan Johnson has since criticised the prime minister for suggesting the public is to blame for rising cases.
People have been "extremely compliant and obedient" but the message hasn't always been clear, he said.
Meanwhile, former health secretary Jeremy Hunt has called for more "unifying messages" from the UK's four nations.
"Wherever possible it is much better to stick together, because simplicity of messaging is one of the things that will make the biggest difference in terms of complying with the rules," he said.
The devolved nations have their own powers over coronavirus restrictions, and their leaders made separate televised addresses on Tuesday evening.
Scotland's Deputy First Minister John Swinney acknowledged the new rules banning people from visiting other people's homes were "difficult and disruptive" and said they would be reviewed every three weeks.
"No one wants to have this in place a moment longer. The more public compliance, the more successful we will be," he told BBC's Breakfast.
Wales' First Minister Mark Drakeford urged people not to let the virus "take a hold of our lives again", and Northern Ireland's First Minister Arlene Foster said tougher restrictions should act as a "wake-up call" that "we are not out of the woods".
A televised address from the prime minister is not the rarity it once was, but it's still a big moment.
The gravity of the situation is such that, Boris Johnson's argument goes, a renewed national effort is required to bring the virus back under control.
Behind the echoes of wartime rhetoric and Johnsonian linguistic flourishes was a simple message; stick with it for six months and we'll get through this.
But as he acknowledged, there are some who say he's taking the wrong decisions and the public's patience for further restrictions may not be what it was six months ago.
There was optimism that better days lay ahead but a vaccine and mass testing were "hopes and dreams" not the reality, not now.
Scotland's First Minister had gone further so comparisons will be inevitable; which tactics will work?
While England and the UK's nerve is being tested again, so too is the prime minister and the government's leadership and its strategy.
The prime minister told MPs on Tuesday that the new rules were "carefully judged" to achieve the maximum reduction in the R number - which measures how quickly the virus is spreading - while causing "the minimum damage to lives and livelihoods".
The latest R estimate for the whole of the UK is between 1.1 and 1.4.
And the number of UK cases rose by 4,926 on Tuesday, government figures showed, with deaths increasing by 37.
What are the new rules?
In England:
Office workers are being told to work from home again if possible Penalties for not wearing a mask or gathering in groups of more than six will increase to £200 on the first offence From Thursday 24 September, all pubs, bars and restaurants will be restricted to table service only. Takeaways can continue Also from Thursday, hospitality venues must close at 22:00 - which means shutting then, not calling for last orders (in Scotland the same curfew rule comes into force on Friday) Face coverings must be worn by all taxi passengers from Wednesday Retail staff and customers in indoor hospitality venues will also have to wear masks from Thursday, except when seated at a table to eat or drink From Monday 28 September, only 15 people will be able to attend weddings and civil partnerships, in groups of six. Funerals can still take place with up to 30 people Also from 28 September, you can only play adult indoor sports in groups of less than six The planned return of spectators to sports venues will now not go ahead from 1 OctoberIn Scotland:
People across Scotland are being advised not to visit other households indoors from Wednesday 23 September onwards. This will become law from Friday There will be exceptions for those living alone, or alone with children, who form extended households. The rules will also not apply to couples who do not live together, or to tradespeople or for the provision of informal childcare - such as by grandparents From Friday, pubs and restaurants will have to close by 22:00 The first minister urged people not to book overseas travel for the October school holidayIn Wales:
Pubs, cafes and restaurants in Wales will have to close by 22:00 from Thursday - and sales of alcohol from off-licences and supermarkets will also be stopped after that time Pubs will also be required to provide table service onlyIn Northern Ireland:
From now, people cannot meet anyone who they don't live with inside their home There are only limited exceptions.How will the new rules affect you? Tell us by emailing haveyoursay@bbc.co.uk.
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