Boris Johnson and Matt Hancock have both tested positive for coronavirus, while Chris Whitty is also self-isolating with symptoms.
The prime minister, the health secretary and England’s chief medical officer have been at the forefront of the government’s response to the pandemic.
Johnson is the first world leader to have confirmed to have contracted the virus.
“I am now self-isolating, but I will continue to lead the government’s response via video-conference as we fight this virus. Together we will beat this. #StayHomeSaveLives,” the PM wrote on Twitter on Friday.
“Thank you to everybody who is doing what I’m doing: working from home to stop the spread of the virus from household to household,” he said.
Downing Street refused to comment on Johnson’s pregnant fiancé Carrie Symonds, but said the PM was self isolating for seven days.
Johnson noticed he had mild symptoms yesterday afternoon and was tested in No.10.
He got the results of the test at midnight last night and has been in self-isolation in No.11 Downing Street, which is now serving entirely as the prime minister’s office and home. Johnson lives above the office in his flat.
The PM will work from the office and the study in No.11 “which has been kindly vacated by the chancellor” and full video conferencing kit has been installed, Downing Street said.
“The guidelines that will apply to the prime minister are those that say you need to isolate for seven days,” the PM’s spokesperson said.
“For now the prime minister’s symptoms are mild and he is continuing to do all the same functions he was performing before, the only difference is he will now have to do that via teleconferencing”.
The spokesperson added: “You can see the PM and see he is very much getting on with the job.
Downing Street said the doors between No.10 and No.11 have been closed off to all other staff who work in the building.
All No.10 staff have been told to observe Public Health England (PHE) guidelines and will remain two metres apart from the PM at all times in the event they were to have contact.
Staff making meals for Johnson will knock on his door and leave the food outside before safely departing.
“It’s very easy to close the door between No.10 and 11 and the door between No.11 and 12 and to make it a house which is isolated from those other two bits of the building, and that’s what’s happened,” the PM’s spokesperson said.
No.10 is considered a workplace rather than a household so staff do not need to self isolate unless they suspect they have symptoms.
But “it’s certainly the case that there are other people on No.10 who have self isolated as a result of having coronavirus symptoms”, the spokesperson said.
Rishi Sunak will work from his office in the Treasury. A spokesman for the chancellor he has not had any symptoms and therefore has not been tested for coronavirus and is not self-isolating.
If Raab was also ill, the PM has the power to delegate responsibility to any of his ministers, a No.10 spokesperson said.
Buckingham Palace has confirmed the Queen last saw Johnson just over two weeks ago.
A spokesperson said: “Her Majesty the Queen remains in good health. The Queen last saw the Prime Minister on the 11th March and is following all the appropriate advice with regards to her welfare.”
US president Donald Trump wished Johnson a speedy recovery in a phone call on Friday.
A Downing Street spokesperson said: “Prime minister Boris Johnson spoke with US president Donald Trump today.
“The president wished the Prime Minister a speedy recovery from coronavirus.
“They agreed to work together closely, along with the G7, the G20, and other international partners, to defeat the coronavirus pandemic.”
Earlier in the week it was announced that the Prince of Wales was also suffering “mild symptoms” of the disease. On Thursday night Charles was seen for the first time since testing positive.
The latest figures from the Department of Health, released on Thursday, showed a total of 578 people who tested positive for coronavirus in the UK have died.
Johnson’s positive test was announced as police began fining people breaching coronavirus lockdown rules, less than 24 hours after new laws were brought into force
Duncan Selbie, the chief executive of Public Health England is also self-isolating with symptoms.