Boris Johnson tells 1.4m they must stay in for 12 WEEKS and everyone else should avoid going out

In dramatic actions not seen since World War Two, the PM drastically ramped up Britain's battleplan - shutting down mass gatherings and urging everyone to stop non-essential travel and contact with others.

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He said that means all Brits (around 66million people) staying out of pubs, clubs, theatres and cinemas for weeks - and potentially months into the summer.

All who can can should work from home, he said.

The over 70s, those who are pregnant, and anyone with underlying health conditions (around 20million Brits) should try not to leave their homes if they can, and avoid crowded spaces immediately.

This will continue for the "long haul" - likely weeks or months.

And those with severe illnesses like cancer (around 1.4million Brits) must start cocooning themselves in their homes and get food delivered in from this weekend.

They will be shielded from social contact for around 12 weeks.

The 'social distancing' guidelines advise people not to visit vulnerable and elderly family and friends - and could mean Mother's Day is effectively cancelled.

It comes as 55 Brits have been killed by the illness, with more than 1,500 cases across the country.

The number of cases could DOUBLE every five or six days if Britain doesn't take "draconian" action now, the PM warned the country, in the most drastic action taken so far to tackle the disease.

The PM announced major crackdown rules including:

• Whole families with symptoms such as a cough or a temperature should stay at home for TWO WEEKS to stop spreading it on to anyone else
• From tomorrow, the Government will no longer support mass gatherings either, meaning concerts and all major sporting events are likely to be cancelled
• Pregnant women will be told to avoid social contact with others too - sparking fresh fears for anyone expecting
• The PM refused to rule out drastic curfews like in other countries
• London is at the centre of the outbreak and was ahead of the rest of the country
• Schools will stay open for now - but they will be told to send kids with a cough home to stop the spread

Levelling with a worried nation in a dramatic No10 press conference, Boris said: "Clearly what we’re announcing today is a very substantial change in the way we want people to live their lives, and I can’t remember anything like it in my lifetime.

"I don’t think there’s really been anything like it in peacetime.

"It’s a very considerable, psychological, behavioural change that we’re asking you, we’re asking the public, the nation to do.

"But I’ve absolutely no doubt that we can do it, that we can do it together."

It came as President Emmanuel Macron tonight announced a total shutdown of France with its borders closed and all social gatherings banned from tomorrow.

The lockdown will be enforceable by law - unlike in Britain.

And Donald Trump recommended a drastic shutdown of the US too - with the President even considering a nationwide curfew.

Boris said: "We are asking people to do something difficult and that will disrupt their lives."

But he stressed that the most vulnerable were the focus of the new measures.

The number of cases has spiralled faster than experts thought, prompting the Government to push ahead with measures quickly, he said.

In a stark change from last week, Chief Scientific Adviser Sir Patrick Vallance said Britain is now entering “the fast growth part of the upward curve”.

Five days ago during the trio’s last press conference, his modelling predicted the contagion’s peak was 10 to 14 weeks off.

Boris added: "I know we are today asking a lot from everybody, but I can tell you people and businesses are responding with amazing energy and creativity.

"I want to thank everybody for the part you are playing, and are going to play.";

It came as actor Idris Elba tonight revealed he had caught Covid-19 and was in self-isolation too.

Brits who feel ill should stay at home for at least 14 days - which includes the whole family if you live with other people.

Sick people should not go out of the house - even to buy food or essentials. Going for a run or walk is allowed, but only at a safe distance.

A report that the government expects eight million people to be hospitalised was only “the reasonable worst case scenario”, No10 insisted yesterday.

A leaked briefing from Public Health England suggested the grim figure was now the likely overall number.

Health Secretary Matt Hancock said in the Commons the measures would be extreme, and added: "We are in a war against an invisible killer and we have to do all we can to stop it."

The PM also didn't mention the role of the army - or whether troops could be on the streets soon to help deal with the outbreak.

Boris did not comment on the planned EU travel ban the bloc announced - and whether Britain would be taking part.

All European countries are set to lock down their external borders within days to stop the spread.

It's unclear how many people will have to stay at home as a result of yesterday's announcement.

And Boris was keen not to say that pubs and restaurants will have to shut - only that Brits should stay away from them.

Yesterday's actions comes after Italy, France, Spain, Germany and several other nations have revealed lockdowns of schools and public places, cancelled flights in and out of the country, and shut their borders.

There was no indication of just how long these extreme measures could be in place for, but Professor Chris Whitty insisted it would be a "prolonged period".

He said earlier: "We should not be under any illusions that... we should just do this for a couple of weeks."

Boris singled out Londoners too, telling them they were the worst hit part of the UK.

They were "ahead of the curve" and must act now to stop spreading it across the country.

London Mayor Sadiq Khan said residents should avoid "all non-essential social contact" tonight.

All visits to pubs, clubs and other venues should stop with immediate effect.

Meanwhile, Mr Hancock is preparing to reveal emergency legislation to the Commons tomorrow to give extra powers to the Government to tackle the crisis.

It could include the powers to detain people suspected of having Covid-19, or slapping a fine on them instead.

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