In office, Boris Johnson liked to see himself as a latter-day Winston Churchill. But the Covid report describing his toxic, chaotic and indecisive No 10 ought finally to put paid to any delusions that he had the qualities necessary to be a prime minister, let alone one guiding a country through a deadly national emergency.

The claim among Johnson’s supporters that he could make a political comeback also now looks increasingly dead in the water.

Johnson’s opponents are already seeking to blame a “Boriswave” of post-Brexit migration on the former prime minister, questioning his political judgment on an area of policy that matters to many voters.

But the Covid report is far more damning about his lack of personal leadership and direction – faults that showed up later in his time at No 10 during the Partygate scandal that unfolded on his watch.

The report may not reveal anything truly new about Johnson’s character but the official conclusion that more lives could have been saved if not for a “lost month” of inaction in February 2020 is highly damaging for the former politician.

In the words of the Covid-19 Bereaved Families group, it is “devastating to think of the lives that could have been saved under a different prime minister”.

Perhaps the most critical passage of the report is the confirmation that Johnson was at a government country retreat in Chevening House receiving no daily updates during half-term week of February 2020, while Covid was ripping through China, spreading in Italy and already confirmed as present in the UK.

“It does not appear that he was briefed, at all or to any significant extent, on Covid-19 and he received no daily updates,” it found. He did not chair a single meeting of the government’s emergency Cobra committee during that month.

The report also concluded that Johnson’s personality contributed to failings in the response, saying he was “acting in accordance with his own optimistic disposition” and accepting assurances that everything necessary was being done.

It said many of these assurances came from Matt Hancock, the health secretary, described by the report as having a reputation “for overpromising and underdelivering”.

“Mr Johnson should have appreciated sooner that this was an emergency that required prime ministerial leadership to inject urgency into the response,” concludes the inquiry, chaired by the retired judge and cross-bench peer Heather Hallett.

The report itself has some critics, including Johnson’s former adviser Dominic Cummings, who claims it involves a “vast rewriting of history” and blames scientific advisers for pushing a “do nothing” option rather than politicians. “The lawyers have paid themselves millions and made understanding of what happened even worse,” he claimed after the publication. Others say the report has cost a lot of money and time without revealing much not already in the public domain.

However, it sets out a clear timeline of the complacency in No 10 about the emerging pandemic in early 2020. And if nothing else, it is an official reminder that Johnson failed the country at a time of critical national need. He was the prime minister, not his advisers, or scientists.

Text messages from Cummings reveal Johnson’s attitude at the time was not sufficiently engaged, even on the day he held his first national press conference about the UK’s response to the global health emergency on 3 March 2020.

Johnson “doesn’t think it’s a big deal … his focus is elsewhere, he thinks it’ll be like swine flu and he thinks his main danger is talking economy into a slump”, Cummings wrote in March, after the conference at which Johnson had talked about how he was still shaking hands with hospital patients.

The inquiry underlines that Johnson “should have been advised – and should himself have appreciated earlier – that this was an emergency that required prime ministerial leadership”. During those critical early months, he did not provide it.