Boris Johnson remains in hospital following his admission on Sunday with continuing coronavirus symptoms, as ministers resisted pressure to set out an “exit strategy” from the lockdown.

Foreign Secretary Dominic Raab said the Prime Minister remained in charge of the Government despite remaining under observation at St Thomas’s Hospital, London.

But at the daily Number 10 news conference, he faced repeated questions as to how Mr Johnson could cope with demands of the premiership if he was sick enough to require hospital treatment.

Earlier Downing Street, which had previously described his symptoms as “mild”, switched to describing them as “persistent”.

They included a cough as well as a continuing high temperature, 10 days after he first tested positive for the coronavirus.

Meanwhile, the latest official figures showed 5,373 patients have died in hospital after testing positive for coronavirus in the UK as of 5pm on Sunday – and increase of 439 on the previous day.

The Prime Minister’s official spokesman said Mr Johnson had been taken to hospital on the advice of his doctor and as a “precaution”, and that it was not an emergency admission.

The spokesman said that he remained in touch with colleagues in Number 10 and that he was continuing to work from his bed on official papers delivered in his ministerial red box.

Mr Raab, who as First Secretary of State stood in for the Prime Minister at the Government’s daily coronavirus “war cabinet”, said his team were continuing to work “full throttle” to ensure his instructions were implemented.

“He’s in charge, but he’ll continue to take doctors’ advice on what to do next,” he said.

“I spoke to the Prime Minister over the weekend. He is being kept abreast of all the relevant developments.”

In a tweet, Mr Johnson confirmed he was still showing symptoms of the virus but said he remained in “good spirits”.

“Last night, on the advice of my doctor, I went into hospital for some routine tests as I’m still experiencing coronavirus symptoms,” he said.

“I’m in good spirits and keeping in touch with my team, as we work together to fight this virus and keep everyone safe.”

In other developments:

– MPs have called for social media companies to be held to account for the spread of conspiracy theories online linking 5G technology to the coronavirus outbreak;

– The Local Government Association warned councils will be forced to shut parks if people keep breaking social distancing rules;

– The Foreign Office has announced further flights to repatriate British nationals stranded in India, Nepal, the Philippines and South Africa;

– A detachment of 40 soldiers from the Scots Guards is helping expand St Mary’s Hospital on the Isle of Wight to provide an additional 200 beds for Covid-19 patients.

Meanwhile, Mr Raab rejected calls for ministers to set out an exit strategy from the lockdown amid mounting concern at the economic devastation that is being wrought.

New Labour leader Sir Keir Starmer called on the Government over the weekend to spell out how it intended to lift the restrictions as the outbreak receded.

However, Mr Raab warned it was essential not to distract from the need to maintain social distancing as the epidemic approached its peak.

“The risk is if we start taking our eye off the ball, of tackling the coronavirus, stopping the spread and getting through the peak, we risk delaying the point at which we could in the future take those decisions on easing restrictions,” he said.

His comments were echoed by the chief medical officer for England – Professor Chris Whitty making his first public appearance since ending his self-isolation – who said it would be a “mistake” to discuss exit strategies until it was clear the peak had passed.

“The key thing is to get to the point where we are confident we have reached the peak and this is now beyond the peak,” he said.

“At that point, I think it is possible to have a serious discussion about all the things we need to do step-by-step to move to the next phase of managing this.”

He acknowledged, however, that in deciding when to ease the restrictions, the economic damage caused by the lockdown would be a factor.

“Anything that has an impact on the socio-economic status, particularly of people who are more deprived, will have a long-term health impact as well,” he said.

“We have to, in our exit strategy, balance all of these different elements which can be in tension.”