Boris Johnson has spent a second night in intensive care as he continues to receive treatment for coronavirus.
Mr Johnson is being kept in St Thomas’ Hospital in London “for close monitoring”, Downing Street said.
The PM is “comfortable, he’s stable, he’s in good spirits”, said health minister Edward Argar on Wednesday.
No 10 also suggested the three-week review into whether the coronavirus lockdown could be eased would not go ahead as planned on Monday.
Asked on BBC Breakfast when the measures might be lifted, Mr Argar said the scientific evidence “isn’t yet there to allow us to make us a decision”.
“We have to be over that peak before we can think about making changes,” he said, adding: “It’s too early to say when we will reach that peak.”
Foreign Secretary Dominic Raab, who is deputising for the PM, said on Tuesday he was “confident” the PM would recover from this illness, describing him as a “fighter”.
Speaking at the Downing Street coronavirus briefing, he said Mr Johnson was receiving standard oxygen treatment and was breathing without any assistance, such as mechanical ventilation or non-invasive respiratory support.
The prime minister was admitted to St Thomas’ on Sunday, on the advice of his doctor, after continuing to display symptoms of a cough and high temperature 10 days after testing positive for the virus.
Mr Raab said the prime minister was being monitored closely in critical care, as was usual clinical practice.
Describing Mr Johnson as not only a boss but “also a friend”, Mr Raab said: “All of our thoughts and prayers are with the prime minister at this time, with Carrie, and with his whole family.
“And I’m confident he’ll pull through, because if there’s one thing I know about this prime minister, he’s a fighter. And he’ll be back at the helm, leading us through this crisis in short order.”