Prime Minister Boris Johnson has tested positive for coronavirus and is self-isolating in Downing Street.
He said he had experienced mild symptoms over the past 24 hours, including a temperature and cough, but would continue to lead the government.
Health Secretary Matt Hancock said he had also tested positive while England’s Chief Medical Officer, Prof Chris Whitty, has shown symptoms.
Another 181 people died with the virus in the past day, figures showed.
It takes the total number of UK deaths to 759, with 14,543 confirmed cases.
The daily coronavirus news conference was led by Cabinet Office minister Michael Gove, alongside deputy chief medical officer Dr Jenny Harries and NHS chief executive Simon Stevens.
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They announced plans to begin a mass testing programme of all health service staff, starting with critical care teams, at the start of next week. It will later be expanded to cover social care staff too.
“This will be antigen testing – testing whether people currently have the disease – so that our health and social care workers can have security in the knowledge that they are safe to return to work if their test is negative,” Mr Gove said.
Mr Stevens said the number of tests being done by the end of next week would be double that being done today.
He also announced plans for two further field hospitals in Birmingham and Manchester, similar to that being readied at the ExCel centre in east London. More would follow those three, he added.
The government has imposed strict restrictions on everyday life designed to slow the spread of the virus.
Mr Gove said the public response to those had been “fantastic” and praised “the national solidarity being shown in the fight against this disease”.
He said scientific analysis suggested the rate of infection had been doubling every three to four days, but adhering to the strict social distancing rules would help to reduce the pressure on the NHS.
Working from home
Mr Johnson is thought to be the first world leader to announce they have the virus.
He was last seen on Thursday night, clapping outside No 10 as part of a nationwide gesture to thank NHS staff and carers.
Shortly after Mr Johnson’s announcement, Mr Hancock said he had been “working from home over the last couple of days” with mild symptoms of the virus, and would be self-isolating until next Thursday.
And Prof Whitty, who has been meeting the prime minster and Mr Hancock regularly, later announced he was self-isolating.
In a video on his Twitter account, Mr Johnson, 55, said: “I’m working from home and self-isolating and that’s entirely the right thing to do.
“But, be in no doubt that I can continue, thanks to the wizardry of modern technology, to communicate with all my top team to lead the national fight-back against coronavirus.
“I want to thank everybody involved and, of course, our amazing NHS staff.”
“So thank you to everybody who’s doing what I’m doing, working from home to stop the spread of the virus from household to household,” he added.
“That’s the way we’re going to win.”
Earlier this week the prime minister’s spokesman said if Mr Johnson was unwell and unable to work, Foreign Secretary Dominic Raab, as the first secretary of state, would stand in.
The prime minister’s fiancée, Carrie Symonds, who is several months pregnant, is also self-isolating, although it is not known if they are still living together.
Pregnant women are advised to be particularly stringent when following social distancing advice, and minimise social contact for up to 12 weeks.
Maybe it was inevitable.
One of the first moments that raised eyebrows in the course of the UK outbreak was when health minister Nadine Dorries came down with coronavirus.
Then, last week, we discovered that some key staff in No 10, including the prime minister’s chief Brexit negotiator David Frost, were self-isolating with suspected symptoms.
A fair number of MPs took themselves off into isolation for fear of having contracted the infection.
Their remaining colleagues were continually ordered to sit far apart on the green benches, before finally, this week, Parliament itself closed early, with no certain date for a return of normal business.
Still, the news this morning that the prime minister himself has contracted coronavirus felt like a shock.
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Neither the PM’s senior adviser Dominic Cummings nor Chancellor Rishi Sunak – with whom Mr Johnson has recently appeared alongside – has symptoms. They have not been tested.
A Buckingham Palace spokesman confirmed the Queen, 93, saw Mr Johnson more than two weeks ago on 11 March, and she is in good health.
The pair usually meet weekly for the prime minister’s audience with the Queen, but the most recent meetings have been over the phone.
The Prince of Wales also tested positive for the virus earlier this week. The 71-year-old is said to be displaying mild symptoms “but otherwise remains in good health”, a spokesman said.
Among the other public figures to be self-isolating is Labour’s Angela Rayner, who said on Friday she was showing symptoms of the virus.
Other world leaders including Canada’s Justin Trudeau and Germany’s Angela Merkel have self-isolated after coming into contact with people who have tested positive for the virus, which causes the disease Covid-19.
Concerns have been raised about whether Brazilian President Jair Bolsonaro may possibly already have the virus. He has twice said that his test came back negative, but has refused to provide proof.
Politicians including Labour’s shadow home secretary Diane Abbott shared messages to the PM, wishing him a “speedy recovery”.
The SNP’s Westminster leader Ian Blackford said Mr Johnson’s diagnosis “sadly shows nobody is immune”.
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Former Chancellor Sajid Javid and ex-Health Secretary Jeremy Hunt both said the whole country was thinking of Mr Johnson, and praised him for his “strong leadership”.
Meanwhile, the president of the European Council, Charles Michel, told Mr Johnson: “Europe wishes you a speedy recovery.”
In other developments:
- Police forces in England and Wales have fined people for ignoring guidance issued to prevent the spread of coronavirus.
- The UK’s chief scientific adviser Sir Patrick Vallance has said he expects the number of coronavirus cases to increase over the next two to three weeks, and then start to gradually decrease due to the current lockdown.
- Mayor Sadiq Khan has warned Londoners there will be “a large number” of deaths and temporary mortuaries will be set up across the capital.
- The Ministry of Justice says 27 prisoners, in 14 prisons, have tested positive.
- Italian restaurant chain Carluccio’s is facing collapse, after warning it is facing permanent branch closures due to coronavirus.
- The number of people who have volunteered to help the NHS has reached 700,000. The government originally set a target of 250,000 but increased it to 750,000 after a huge response.
- More than 7,000 former nurses and midwives have signed up to return to the profession.
- Tesco has said that online shoppers will have their deliveries capped at 80 items from now on, while supermarkets will also use a government database of 1.5 million vulnerable shoppers in England to help prioritise delivery slots.
- The Queen’s birthday parade, the Trooping the Colour, will not go ahead in its usual form, and other options are being considered.