Boris Johnson was admitted to hospital on Sunday night, and spent the night there. Housing secretary Robert Jenrick said the measure was a "precautionary step" and that the cabinet "[hoped] that as a result of tests [the PM] will be able to come back to Downing Street as soon as possible".
"He's still very much in charge of the government," Mr Jenrick said. Today's briefing is set to be taken by foreign secretary Dominic Raab.
In her address on Sunday night, Her Majesty The Queen told the country that "we will succeed" in a challenge she said was "different".
"We will succeed, and that success will belong to every one of us."
She said the "painful sense of separation" reminded her of the plight of child evacuees during the Second World War, but said that "now, as then, we know, deep down, that it is the right thing to do."
The BBC's royal correspondent described the message as an "ambitious broadcast, designed to reassure and to inspire".
In Europe, the Austrian government has made it "compulsory" to wear some kind of mask in all stores. Austria is the latest country to move towards wearing masks as a preventative measure, joining the US, whose public health advisory body released "voluntary" guidance suggesting that citizens wear masks.
And in Singapore, some 20,000 workers have been quarantined for two weeks as cases begin to sharply rise.
The next Leaders Council update will follow this evening.
