New England-wide measures which could see hospitality businesses shut are being considered by the government to slow a surge of coronavirus cases.
A short period of tighter restrictions – lasting a few weeks – could be announced in the next week, BBC political editor Laura Kuenssberg said.
Schools and most workplaces would be kept open during those weeks.
Health Secretary Matt Hancock has told the BBC the government is “prepared to do what it takes” against Covid-19.
UK coronavirus cases up by 3,395 on Thursday
Which areas are under lockdown?
Speaking to BBC Breakfast, the health secretary said there had been an “acceleration” in the number of coronavirus cases in the last couple of weeks, and the number of people admitted to hospital with coronavirus was doubling about every eight days.
He stressed it was “critical” that people follow social distancing guidelines and local lockdown rules – where they apply – to “avoid having to take serious further measures”.
The government bases its decisions on the Office for National Statistics’ weekly infections survey about the spread of coronavirus in England and Wales, the health secretary said.
It is estimated that 59,800 people in the community in England had coronavirus in the week to 10 September – roughly one in 900 people.
That equated to about 6,000 new cases each day in England. The number of cases that had been picked up in official daily tests climbed from 1,940 to 2,919 during that week, suggesting that more than half of all cases are still going undetected.
It comes as new rules have been announced for the North West, Midlands and West Yorkshire in England, which come into force from Tuesday.
At a meeting on Wednesday night, the government’s chief scientific adviser and medical officer forecast that there would be a significant number of deaths by the end of October if there were no further interventions.
The possible measures being discussed – described by the government as a “circuit-break” – include asking some hospitality businesses to close, or limiting the opening hours of some pubs and restaurants nationwide.
No final decisions have yet been reached on the next course of action.
Labour’s shadow health secretary Jonathan Ashworth has said it is “not surprising national restrictions are back on the table” as the UK’s testing system is “collapsing”.
Basic maths shows us how quickly coronavirus cases can, theoretically, soar.
Around 4,000 infections a day, doubling every eight days, would be 128,000 new daily cases by the end of October.
That is not guaranteed to happen, and a change in our behaviour, the “rule of six” or restrictions like those in north-east England could improve the situation.
The point of a national “circuit-break” would be to achieve a controlled drop in the levels of coronavirus without needing a full lockdown.
This does two things, obviously it helps avoid having very high levels of the virus that could overwhelm hospitals.
But it also gives us more options. Any contact tracing programme or system of local lockdowns is far easier to implement when levels of the virus are low. The higher the number of cases, the fewer targeted measures the government has to use.
The problem is once the circuit-break is over, cases would begin to rise again and it may take multiple circuit breaks to get us through winter.
The virus is now understood to be doubling every seven to eight days, with more than 3,300 new cases reported on Thursday.
And having been in single figures for much of the past six weeks, the daily number of deaths of people within 28 days of a positive coronavirus test has risen above 20 for the past three days.
In France and Spain, a rapid surge has seen both countries record more than 10,000 new positive cases a day, more than 20 times higher than the level in June.
Meanwhile, new restrictions have come into force in north-east England, affecting nearly two million people. The measures ban people from meeting other households, and restaurants and pubs will have to shut at 22:00 BST.
And it is understood the government has said no to a request by the local council to close bars and pubs in Leeds at 22:00 BST.
The four nations of the UK are all in charge of their own lockdown restrictions, with Scotland, Wales and Northern Ireland implementing slightly different rules to England.
Options for ministers
Under the so-called “circuit-break”, restrictions could be reintroduced in some public spaces nationwide for a period of a few weeks, but schools and workplaces would be kept open.
One of the ideas suggested by the government’s Scientific Advisory Group for Emergencies (Sage) is that some parts of the hospitality sector could be asked to close.
No 10 is also considering the possibility of limiting the opening hours of pubs and restaurants across the country, as has already happened in some areas.
The health secretary said the government’s current approach was “targeted interventions” and stressed “a national lockdown is the last line of defence”.
“The strategy is to keep the virus down as much as is possible whilst protecting education and the economy,” Mr Hancock added.
“And throw everything at the science which eventually is the way we’re going to spring out of this.”
Prime Minister Boris Johnson is understood to be deeply reluctant to order another national lockdown, where everyone would be asked to stay at home and businesses to close.
Earlier this week he described the potential impact of a second national lockdown on the economy as “disastrous”.
On Thursday morning, Chancellor Rishi Sunak is understood to have presented warnings of the damage to the economy.
Ministers are also concerned about the impact of more restrictions on daily life on those who need treatment for non-Covid related illnesses.
On Friday, parts of north-east England joined other areas across the UK in being under local lockdown rules.
The measures affect Newcastle, Gateshead, Sunderland, Northumberland, South Tyneside, North Tyneside and the County Durham council area.
As well as the ban on households mixing and early closures for pubs and restaurants, people should also only use public transport for essential travel and care homes are closed to visitors.
Read more: North-east England local lockdown begins
There are also local lockdown restrictions elsewhere in the UK – including Birmingham, Greater Manchester, Caerphilly, and the Belfast council area.
In other key developments:
A rapid test can accurately diagnose a coronavirus infection within 90 minutes without needing a specialist laboratory, scientists have said
Personal protective equipment will be free for care homes until next March, as part of a government coronavirus plan for NHS England the winter
British retail sales have continued to increase for the fourth consecutive month, boosted by spending on household goods and DIY, according to official figures
London’s New Year’s Eve firework display will not be taking place this year, Mayor of London Sadiq Khan told LBC
The number of new weekly cases in Europe has exceeded the number reported during the first peak of the pandemic, the head of the World Health Organization in Europe has warned
Figures show nearly two-thirds of adults are now travelling to work again
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