British Prime Minster Boris Johnson has ordered the closure of most retail stores and banned gatherings for three weeks in a stepped-up response to slow the new coronavirus.
The measures Johnson announced in a televised address to the nation last night are more closely aligned with sweeping actions taken in France, Spain and Italy but mark a departure from the British government's previously more relaxed approach to the worldwide Covid-19 pandemic.
Britain has already closed schools, bars and restaurants and urged people to stay at home. But while many followed the instructions, some did not.
The approach has led to confusion and caused alarm to public officials worried about the ever-escalating numbers of cases.
There were growing calls for the government to impose tighter restrictions with more rigorous enforcement.
Johnson said that he was giving "the British people a very simple instruction - you must stay at home".
He offered a list of limited purposes for which leaving home would be allowed, including essential shopping, medical appointments and one form of exercise a day.
Johnson had come under mounting pressure to introduce tougher measures in response to the virus pandemic, including an Italy-style nationwide lockdown, after many people were seen out in public over the weekend not properly observing the government's social distancing recommendations.
Officials at Snowdonia National Park in Wales, which had its "busiest visitor weekend in living memory", had urged the government to be more explicit with its social distancing advice.
They said all the main parking lots would be closed and that they are "exploring options to close down the most popular mountains and sites if the situation continues".
Responding to the visibly high use of parks and the London Underground during the virus pandemic, London mayor Sadiq Khan implored people to stay at home unless they "absolutely need to" move about the city.
British health secretary Matt Hancock expressed frustration as well. He said the government would consider locking down the country if the public kept disregarding calls to stop mingling in groups.
Hancock described those not heeding official recommendations to stay two metres apart from others as "very selfish".
The UK had the 10th highest number of virus cases in the world, 5,903, and the sixth-highest number of virus-related deaths as of yesterday, according to tallies from Johns Hopkins University. British government figures showed 54 more people with the virus had died since Sunday, bringing the country's total to 335.
New infections are increasing at an exponential rate, raising concern the country will be on a trajectory like Italy's in a week or two if containment efforts are not successful.
For most people, the new coronavirus causes only mild or moderate symptoms, such as fever or coughing. But for some older adults and people with existing health problems, it can cause more severe illness, including pneumonia. More than 100,000 people have recovered, mostly in China.
But in the UK, photos of people enjoying the sunny weekend outdoors and of London Underground trains packed with individuals afraid of losing jobs prompted the British government to act with more severe measures.