Prime Minister Boris Johnson is stable in intensive care at the NHS' St Thomas' Hospital in London and has been receiving oxygen treatment, the government has said.
Mr Johnson has not been diagnosed with pneumonia and has not required ventilation for respiratory support, a spokesman said in an update on the Prime Ministers' condition at 12.30pm today.
It is understood he was moved so he could be close to a ventilator if that is needed.
Mr Johnson, 55, is "in very good hands", said Dominic Raab, who is standing in for the PM and chaired the government's daily meeting.
Foreign Secretary Mr Raab is leading the government's response to coronavirus in the Prime Minister's absence and if he were to fall ill, Chancellor Rishi Sunak would take over.
UK Cabinet Office minister Michael Gove is self-isolating at home because a family member is showing symptoms of coronavirus.
The spokesman said the PM was "grateful for all the warm wishes we received over night. Any treatment that he receives is a matter for his doctors."
He added: "The government has a very clear plan which has been set out by the PM. Everyone is very clear what needs to be done and whats to get on with the work he has asked them to do."
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Asked about security arrangements in relation to nuclear weapons and defence, the spokesman said that the Secretary of State and cabinet have national security authority and decisions would be taken by cabinet on basis of collective decision making.
Mr Raab is not able to hire or fire other ministers.
On whether lockdown can be renewed in the PM's absence, the spokesman said there was "no legal need for it to be renewed, not something that can lapse"
Buckingham Palace and the Queen have been kept regularly informed of the PM’s condition.
The Queen has been informed that her weekly audiences will not be going on without the PM.
