The shocking diaries of former chief scientific adviser Sir Patrick Vallance were shared to the public inquiry as he gave evidence.
The inquiry heard of the "shambolic" day on October 25, 2020, when the country was heading towards a second national lockdown.
In a bombshell extract from Sir Patrick’s diary, he quoted Dominic Cummings, the then prime Minister Boris Johnson's chief adviser. as saying: "Rishi [Sunak] thinks just let people die and that's okay". Mr Sunak was then Chancellor.
Former Prime Minister Boris Johnson was said to have been "getting very frustrated" and "throwing papers down" during the meeting, claiming that "most people who die have reached their time anyway".
Sir Patrick wrote: "This all feels like a complete lack of leadership."
The extract read: "PM meeting – begins to argue for letting it all rip. Saying yes there will be more casualties but so be it – ‘they have had a good innings’.
"Not persuaded by (Jon) Edmunds, (Neil) Ferguson, (Jeremy) Farrar. PM says ‘the population just has to behave doesn’t it’.
"Heat maps ‘I have the necrotising maps’ so depressing.
"DC says trajectory will leave us in Nov – much as where we were in 1st week of April.
"Chris quite bullish about being able to take the brakes off more in April…
"Goes on about Gulf War Syndrome again… PM getting very frustrated – throwing papers down.
"PM then back on to ‘most people who die have reached their time anyway’.
"DC arguing we need to save lives – it is not democratically possible to follow another route…
"DC argued again (rightly) that a lockdown’s coming and therefore do it sooner rather than later.
"PM concludes, ‘Looks like we are in a really tough spot, a complete shambles.’
"‘I really don’t want to do another national lockdown’.
"PM told that if he wants to go down this route of letting go, ‘you need to tell people – you need to tell them you are going to allow people to die’…
"Conclusion – beef up the tiers – consider a national lockdown – decide by when.
"DC says ‘Rishi thinks just let people die and that’s okay’.
"This all feels like a complete lack of leadership."
Asked about the diary entry, Sir Patrick told the inquiry he was recording what must have been "quite a shambolic day".
However, the following day’s entry shows Mr Johnson had taken a different view and described the Covid death toll as "terrible".
The inquiry also heard that Sir Patrick wrote that "we have a weak indecisive PM" and described the right-wing press as "culpable" in decision-making on Covid measures.
Asked about the diary entries, Downing Street declined to say whether Mr Sunak thought it would be OK to "just let people die" during the pandemic, saying it would be for the Prime Minister to set out his position during evidence before the Covid Inquiry.
"The Prime Minister is due to give evidence before the inquiry at the time of their choosing. That’s when he’ll set out his position," Mr Sunak’s official spokesman said.
The spokesman said a number of people will be setting out their views of the period, but "rather than respond to each one in piecemeal, it’s right that it is looked at alongside other evidence".
The inquiry also heard how Mr Johnson sometimes struggled to retain scientific information, was "clutching at straws" and at one point queried whether Covid was spreading "because of the great libertarian nation we are".
One of Sir Patrick's diary entries from May 4, 2020 said: "Late afternoon meeting with the PM on schools. My God, this is complicated. Models will not provide the answer. PM is clearly bamboozled."
Other entries, also written in May 2020, said: "PM asking whether we've overdone it on the lethality of this disease. He swings between optimism pessimism, and then this.
"PM still confused on different types of test. He holds it in his head for a session and then it goes."
In June, Sir Patrick wrote: "Watching the PM get his head round stats is awful. He finds relative and absolute risk almost impossible to understand."
Later, in September 2020, Mr Johnson is talked through some graphs, after which Sir Patrick wrote: "It is difficult, he asks questions like 'which line is the dark red line?' - is he colourblind? Then 'so you think positivity has gone up overnight?' then 'oh god bloody hell'. But it is all the same stuff he was shown six hours ago."
Under questioning by Andrew O'Connor KC, counsel to the inquiry, Sir Patrick said: "I think I'm right in saying that the prime minister gave up science at 15.
"I think he'd be the first to admit it wasn't his forte and that he struggled with the concepts and we did need to repeat them. Often."
However, Sir Patrick said this issue was not unique to the UK and advisers in other European countries had suggested at least one other leader had also struggled.
"So I do not think that there was necessarily a unique inability to grasp some of these concepts with the prime minister at the time, but it was hard work sometimes to try and make sure that he had understood what a particular graph or piece of data was saying."