UK government ramps up coronavirus response

In the first of the government's daily briefings, Johnson said everyone should avoid non-essential contact with others as he urged people to stay away from pubs, clubs and theatres. He also advised the public to stop all non-essential travel.

"We need people to start working from home where they possibly can and you should avoid pubs, clubs, theatres and other such social venues," he said.

Asked whether pubs and restaurants would be closed, Johnson said that while the government has the powers to do so "if necessary", he did not believe these would need to be used.

Johnson said that according to the Scientific Advisory Group for Emergencies (Sage), it looks as though we are now approaching the fast growth part of the upward curve in the number of cases. "Without drastic action, cases could double every four or five days," he said.

In addition, Johnson said that if one person in a household develops a cough or a temperature, the entire household must now self-isolate for 14 days.

The PM also urged all unnecessary visits to care homes to stop in order to protect the vulnerable.

From Tuesday, mass gatherings will not be supported by emergency workers in the way they normally are, Johnson said.

"This advice about avoiding all social contact is particularly important for people over 70, for pregnant women and for those with some health conditions," he said. Groups who are particularly at risk will be advised to self-isolate for 12 weeks from this weekend.

England’s chief medical officer, Professor Chris Whitty, said the UK’s testing regimen was robust. There is "complete surveillance" testing in intensive care, while hospitals are testing patients with pneumonia and GPs are testing in the community, he said.

Whitty said testing will be scaled up in the next few weeks and move out into the wider community. He noted that 44,000 tests had already been conducted.

Earlier on Monday, the World Health Organization said nations weren't running enough tests and that "every suspected case" should be tested.

Whitty said the new advice on social distancing could last "weeks to months" and maybe even longer depending on how things pan out. "We've got to see this as a long game," he said.

Wrapping up the press conference, Johnson said: "What we are announcing today is a very substantial change in the way that people live their lives.

"But I’ve absolutely no doubt that we can do it. We can do it together. Everybody understands the need."