Up to 4.5 million people most at risk from Covid will be told to stay at home under a new shielding plan based on health, age and weight, according to a report.
Letters with tailored advice are to be sent to individuals based on a new 'risk model' which will factor in underlying health conditions, age, sex and weight.
This measure will be introduced first for areas with high rates of infection but a Whitehall source told The Sunday Telegraph 'if the rate is so concerning across the whole of England we are prepared to do it on a blanket basis.'
It comes amid a surge in coronavirus cases, with a rise of 3,497 yesterday – the highest Saturday uptick in four months. Another nine died of coronavirus, bringing Britain's death toll to 41,623.
There are grave fears that we may 'lose control of the virus' because it has once again starting ripping through the nation's care homes.
A DHSC spokesperson said today: 'We keep all aspects of our response to the pandemic under review and in line with the advice of our scientific and medical experts.
'Shielding for the clinically extremely vulnerable has been paused since the start of August in most of the country while average rates of coronavirus remain low. Shielding is still advised in specific areas of the country where prevalence of the virus is higher.'
A Department of Health report marked 'official sensitive' and circulated on Friday said that the rate of coronavirus recorded through satellite tests - which are used in care homes - had quadrupled since the start of the month.
Health Secretary Matt Hancock took an emergency update on Wednesday saying that outbreaks had been detected in 43 care homes, according to the Sunday Times.
Sir Mark Walport, the former chief scientific adviser, warned yesterday that we are 'on the edge of losing control' of the pandemic and urged people to work from home where possible.
Public Health England (PHE) data suggests Covid-19 cases are surging among the over-50s, as senior officials last night warned of 'worrying' signs for high-risk groups.
Last week, infections rose by 92 per cent among people in their 50s, 72 per cent among those in their 60s, and 44 per cent among those in their 80s and older.
There was a 20 per cent increase in Covid-related hospital admissions last week on the previous week among those aged 60-75, a 72 per cent increase among 75 to 84-year-olds, and a 67 per cent rise in those 85 and over.
Yvonne Doyle, medical director at PHE, said: '3,539 new cases of Covid-19 have been reported overnight, compared to 2,919 yesterday. Most of these cases are people tested in the community.
'Although younger people continue to make up the greatest share of new cases, we're now starting to see worrying signs of infections occurring in the elderly, who are at far higher risk of getting seriously ill.
'This is a reminder of the ongoing risk as the virus spreads throughout the UK. People should continue to follow social distancing rules, wash their hands regularly and wear a face covering in enclosed spaces.'
Experts who have been swabbing tens of thousands of people in England found 13 people per 10,000 were infected between August 22 and September 7, compared to four per 10,000 between July 24 and August 11.
Weekly cases in men aged 60 to 69 rose from 221 to 352 in the past week, an increase of 60 per cent, while among women in the same age group there was a 72 per cent jump from 219 to 376.
Officials had said that while the rise in cases was apparent in younger age groups, it was likely to move on to older people, which would be followed by an increase in hospitalisations.
In a letter sent out Friday, care home bosses were urged to 'take the necessary action to prevent and limit outbreaks', pointing out that in the last three days there had been an increase in notifications of coronavirus cases in care homes.
At the moment it is the workforce that is most affected, but the letter says that 'clearly' there is a risk that the virus will spread to residents and in some cases already has.
The letter, which was written by Stuart Miller, director of adult social care delivery at the Department of Health and Social Care, said: 'You will know already that we are experiencing a rise in confirmed Covid-19 cases, across the UK population.
'I need to alert you to the first signs this rise is being reflected in care homes too.
'Over the past three days, Public Health England (PHE) has reported an increase in notifications of Covid-19 cases in care homes.
'Testing data has also shown an increase in the number of positive results.
'Currently, the infections are mainly affecting the workforce but clearly there is a risk the virus will spread to care home residents, or to other parts of the care sector.
'Unfortunately, in some care homes with recent outbreaks, this does appear to have occurred, with residents also becoming infected.'
A Department of Health and Social Care spokeswoman said: 'Throughout our coronavirus response we have been doing everything we can to ensure all staff and residents in care homes are protected.
'We are testing all residents and staff, have provided 200 million data-x-items of PPE and ring-fenced £600 million to prevent infections in care homes, with a further £3.7 billion available to councils to address pressures caused by the pandemic, including in adult social care.
'There is a high demand for tests and our laboratories continue to turn test results around as quickly as possible and we plan to rapidly expand it in the coming weeks as well as bringing in new technology to process tests faster.'
Tough new Covid-19 lockdown measures were announced for parts of the UK on Friday as cases continued to rise and as the R number - the reproduction number of coronavirus transmission - climbed above one.
According to Government advisers, the last time R was above one was in early March.
The public has been warned against having a 'party weekend' ahead of rule changes on Monday, when social gatherings in England will be limited to groups of six people both indoors and outdoors, a new restriction dubbed the 'rule of six'.
Police have been dispersing gatherings and handing out fixed penalty notices over the weekend, with one teenager facing a £10,000 fine for hosting a house party with dozens of guests in Nottingham.
The Sunday Telegraph reported that if cases rise to dangerous levels, millions of people deemed high-risk will be asked to shield at home or given advice to protect themselves.
Regarding the plan, a DHSC spokeswoman said: 'We keep all aspects of our response to the pandemic under review and in line with the advice of our scientific and medical experts.
'Shielding for the clinically extremely vulnerable has been paused since the start of August in most of the country while average rates of coronavirus remain low.
'Shielding is still advised in specific areas of the country where prevalence of the virus is higher.'
A Whitehall source told the Telegraph that the shielding measure will first be rolled out in areas experiencing spikes in cases, but that the government is prepared to implement it on a 'blanket basis' if necessary.
Britain had recorded 3,497 new cases of coronavirus as of 9am Saturday, marking the highest Saturday rise since May, as SAGE warned that England is now on the brink of 'losing control' of the virus.
Nine more deaths were also recorded, bringing the total number of people who died within 28 days of a positive test for coronavirus to 41,623. The total number of confirmed cases stands at 365,174.