Prime Minister Boris Johnson warned Sunday the coronavirus outbreak was "accelerating", as fears grew that the crisis in Britain was following the same path as the one devastating Italy.
Johnson's plea came after latest health department figures showed that 233 people have died from COVID-19 in the UK, with the number of those testing positive for the virus standing at 5,018.
That death toll mirrors the same figure declared in Italy on March 7. On Saturday, Rome said that 4,825 people had perished in the country, a third of the world's total.
"The numbers are very stark, and they are accelerating," Johnson said in a statement ahead of a planned press briefing later in the day.
"We are only a matter of weeks -- two or three -- behind Italy. The Italians have a superb health care system. And yet their doctors and nurses have been completely overwhelmed by the demand."
Johnson's warning came amid a growing debate about whether people are taking warnings to socially distance from each other seriously enough and whether or not government should enforce stronger restrictions.
The government has outlined emergency legislation to give police, public health and immigration officers extra powers to contain the outbreak.
London is the city worst affected and Mayor Sadiq Khan told the BBC that police may have to be given powers to enforce social distancing.
"It's really important that the police are focused on the priorities that they've got," he said.
"But clearly, if it is the case that people continue to act in a way that's leading to this disease spreading, then those sorts of things will have to be considered."
On Friday, Downing Street announced stronger measures to try and combat the spread, including the closing of bars, pubs and restaurants as fears that health services could soon be overwhelmed.
Housing secretary Robert Jenrick told Sky TV on Sunday morning that if the public did not follow their advice they will "have to consider other options".
There were also signs of a political fallout. Downing Street denied a "highly defamatory" Sunday Times newspaper story that Johnson's chief adviser, Dominic Cummings, had initially argued against strict measures to contain the virus, in an argument summed up as "if that means some pensioners die, too bad".
Most at risk
The concerns came as authorities in the UK told 1.5 million people most at risk to stay at home for 12 weeks.
As part of the latest measures to try and protect the vulnerable, the government advised those with underlying health conditions such as bone or blood cancers, cystic fibrosis, or who have had an organ transplant to do all they can to shield themselves from the virus, including confining themselves at home for a long period.
"People should stay at home, protect our NHS and save lives," Jenrick said.
He also said the government would get protective gear to NHS staff on the frontline "as soon as possible" as fears the virus could be spreading due to a lack of equipment for medics.
In a further sign of growing concern, environmental and heritage charity the National Trust said it would close all of its parks and gardens.
This reversed an earlier decision to keep them open during the crisis, because of fears over social distancing.