The Prime Minister has said if Brits don't start listening to Government guidelines to social distance and stay six feet apart, he may have to enforce more tougher measures within the next 24 hours like other countries, including Spain and Italy, have.
During the daily press conference at Downing Street on Sunday, March 22, Boris said: "I don't think you need to use your imagination very much to see where we might have to go, and we will think about this very very actively in the next 24 hours.
"We need to think about the kind of measures we've seen elsewhere - other countries that have been forced to bring in restrictions on people's movements altogether, now as I say I don't want to do that."
At the weekend, Brits flocked to beaches, parks and markets despite the PM urging millions to stay indoors to make sure the spreading of the virus is kept to a minimum.
During his conference, Boris warned the NHS could become "overwhelmed" if people don't start taking social distancing responsibly.
He added: "Many, many people do not have access, let's face it, to private green spaces where they can do that and that's why parks, open spaces are so absolutely crucial for our country and for our society.
"But when we do that we have to do that responsibly, my message is you've got to do this in line with the advice, you've got to follow the social distancing rule - keep two metres apart.
"Otherwise if you don't do it responsibly, as you suggest there is going to be no doubt that we will have to bring forward further measures and we are certainly keeping that under constant review.
"Going outside now and taking exercise - you've got to take account of the medical advice and observe social distancing.
"If people can't do that, won't do that, don't do that then yes of course we're going to have to bring in tougher measures."
Boris' warning came as the UK death toll rose to 281.
On Friday, March 20, the government announced that that all pubs, restaurants and gyms would close with immediate effect to try and minimise social gatherings.
Current NHS advice for anyone experiencing coronavirus symptoms such as a high temperature or a dry cough is to stay at home.
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