A ban on pubs and restaurants staying open during the coronavirus outbreak will be enforced "strictly" if necessary through licensing rules, the Prime Minister warned.
Boris Johnson said people have already made a "huge effort to comply" with social distancing policies in a bid to halt the spread of the disease and there had been a "big reduction" in the number of pub-goers.
But he warned it was "becoming clear in order to drive that curve down, to reduce social gathering, we now need to be making absolutely clear that we are going to enforce these closures".
Businesses shut to the public would still be allowed to offer a takeaway service, he added.
When asked by reporters how the ban would be enforced, he said: "Clearly there are licensing arrangements which will make it relatively simple to do, should that really be necessary."
He said the ban would be enforced "strictly" but stopped short of elaborating on measures that could be taken other than possibly indicating that revoking licences may be an option.
It is currently unclear whether police would be drafted in to enforce the ban or what, if any, punishment would await venues flouting the order or people who continue to frequent them.
Instead, he said he thought everybody could see the "imperative in protecting the NHS and saving lives" and would do what was necessary.
Appealing again for the country to take the ban seriously, Mr Johnson added: "I do accept that what we're doing is extraordinary - we're taking away the ancient, inalienable right of freeborn people of the United Kingdom to go to the pub.
"And I can understand how people feel about that.
"But I say to people who do go against the advice that we're getting, the very clear advice that we're getting from our medical and scientific experts, you know you're not only putting your own life, the lives of your family, at risk - you're endangering the community.
"And you're making it more difficult for us to get on and protect the NHS and save lives. And if you comply, if people comply as I say, then we will not only save lives, thousands of lives, but we'll come out of this thing all the faster."
A National Police Chiefs' Council spokesman said: "We expect business owners will want to support the measures designed to keep us all safe.
"We will police as normal. If officers see specified businesses open, they will remind them of the Government advice."