The first positive news about Boris Johnson – he was said to be making “steady progress” and “sitting up in bed” – was blighted by 938 further fatalities, only just short of the peak of 971 in Italy at the height of its epidemic.
Meanwhile, Wales rebelled against the government’s refusal to confirm the lockdown will extend beyond next week, announcing it would not “throw away the gains we have made” by lifting restrictions immediately after Easter.
Mr Raab will chair a meeting of the emergency Cobra committee on Thursday, to try to thrash out an agreed “approach to the review” of the lockdown, due next week.
The foreign secretary will be thrust into the spotlight amid continuing confusion about the extent of his authority and fears of a power vacuum in Mr Johnson’s absence.
For the first time, No 10 described Mr Raab as “deputising for the prime minister” – without the caveat “wherever necessary” – agreeing Mr Johnson was “not working” while in intensive care.
However, Michael Gove and others have argued decisions will be taken through “collective responsibility”, leaving it unclear just how far Mr Raab can lead.
On another significant day in the crisis:
* Rishi Sunak, the chancellor, announced a £750m bailout for charities hit by disappearing donations – but faced criticism that it fell short of the £4bn needed.
* The deputy chief scientific adviser said she was encouraged by admissions to critical care slowing “towards a flat curve” – despite the record death toll.
* She also hinted that schools might reopen before restrictions are eased on other parts of society – but refused to say if that could happen “before the summer”.
* Mr Sunak acknowledged his jobs retention scheme could be hit by fraudsters – but said the priority was getting money quickly to firms that badly need it.
* The chancellor also vowed the UK would leave the post-Brexit transition period on time at the end of December – with Mr Raab now in charge of the trade talks.
Mr Sunak delivered the upbeat update on Mr Johnson at the afternoon press conference, saying: “The latest from the hospital is that the prime minister remains in intensive care, where his condition is improving.
“I can also tell you he has been sitting up in bed and engaging positively with his clinical team.”
But the chancellor refused to lift the lid on plans for easing – or, far more likely, extending – the lockdown beyond the review date of Thursday next week.
Earlier, Mark Drakeford, the first minister of Wales, vowed: “These restrictions will not end then.
“We will not throw away the gains we have made and the lives we have saved by abandoning our efforts just as they begin to bear fruit.”
Mr Drakeford said a lockdown extension would be reviewed and agreed with leaders in London, Edinburgh and Belfast “over the coming days”.
But Mr Sunak said: “I don’t want to start speculating about the future, I don’t think that’s helpful at this juncture.”
He revealed Thursday’s meeting, saying: “There will be a Cobra meeting tomorrow, chaired by the first secretary of state [Mr Raab], involving the devolved administrations to talk about the approach to the review.
“We committed there would be a review in and around three weeks. That review will be based on the evidence and data provided by Sage [the Scientific Advisory Group for Emergencies] which will only be available next week.”
The chancellor insisted the priority remained to stop the spread of the virus, urging people to follow advice and stay at home.