It’s hard to see Dominic Cummings returning to politics now – but just how damaged is Boris Johnson?

Whatever his motivations, Cummings has shone a light on government failings that would have remained in the dark without his fireworks display

Dominic Cummings did not live up to the caricature of himself painted in the run-up to his marathon seven-hour appearance at the health and science select committees. His pre-emptive Twitter blitz led his critics to portray Cummings as a bitter man out for revenge on Boris Johnson after being forced out of Downing Street, who would try to restore a reputation damaged by his infamous trip to County Durham during the first lockdown.

Instead, Cummings emerged as a credible witness after an uncharacteristic mea culpa. He regretted not “hitting the panic button” earlier over a flawed initial reaction to the coronavirus outbreak which could have cost 500,000 lives. He admitted his culpability in a response which still cost tens of thousands of unnecessary deaths and “fell disastrously short of the standards the public has a right to expect of its government”.

Surprisingly, Cummings offered a different version of events on County Durham. He said he moved his family out of London with police permission because of threats to their security, and finally apologised for a “complete disaster” which “undermined public confidence”. His explanation of his “eye test” drive to Barnard Castle was unchanged, and less convincing.

There was a catalogue of criticism of Johnson: Cummings regarded him as “unfit for the job” and it was “completely crackers” he had become prime minister. His most serious charge was that Johnson overruled his advisers to delay last autumn’s second lockdown. This matters because more people died in the second wave than the first. Johnson regarded the first lockdown as a mistake, Cummings said, viewing the economic damage as worse than Covid. He quoted Johnson as repeatedly saying he should have been the mayor in the film Jaws, who kept the beaches open even though a killer shark was on the rampage.

At the outset, Johnson dismissed Covid as a “scare story” like swine flu and, incredibly, even suggested he should be injected with the virus live on television by Chris Whitty, the chief medical officer. He said Johnson changed his mind 10 times a day and contradicted his own policy day after day; he was “like a shopping trolley” crashing from one side of the aisle to the other.

While Cummings’ enemies will accuse him of rewriting history, not all of his criticisms are about the past. With foreign travel still a very live issue, Cummings said “there was no proper border policy because the prime minister did not want a proper border policy” as he wanted to protect the tourism industry.

Cummings’ most damning remarks were reserved for Matt Hancock, the health secretary, whom he accused of being “completely incapable of doing the job”. Remarkably, Cummings said there were at least 15-20 times when Hancock should have been fired, a view he claimed was shared by the then cabinet secretary Mark Sedwill. He accused Hancock of repeatedly lying in meetings (a charge the health secretary will deny) and mishandling pandemic planning, personal protective equipment and mass testing; and wrongly promising Johnson hospital patients would be tested for Covid before being discharged to care homes.

Cummings deliberately ensured Hancock will have a lot of questions to answer when he appears before the same group of MPs on 10 June. His evidence also gives Johnson a big dilemma when he reshuffles his cabinet: if he sacks or moves Hancock, it would validate Cummings’ criticism. Ominously for Hancock, Johnson did not rush to his defence today. Cummings’ suspicion that he was kept in post so he could become the fall guy might come to pass.

It is hard to see Cummings ever returning to politics after this. He conceded that everyone would agree that the less we hear from him in future, the better. Cynics will see his defence of Rishi Sunak – saying his image as an opponent of lockdown was “completely wrong” – was a downpayment for a possible comeback.  But any future leader knows that hiring Cummings comes with a “I May Destroy You” warning. He has now publicly blown up three Tory leaders under whom he has worked – Iain Duncan Smith,  David Cameron and now Johnson.

How damaging is it for Johnson? The public will likely give the prime minister the benefit of doubt for mistakes made in the uncharted waters when the pandemic broke out. They may be less forgiving about the delay over imposing the second lockdown. Johnson will hope the people’s verdict will be coloured by the “here and now” success of the vaccine rollout, and their hostility to Cummings over his Durham trip ensures he is less trusted than Johnson himself.

But Johnson is not out of the woods. Whatever his motivations, Cummings has shone a light, undoubtedly allowing the country to discover things that would have remained in the dark without his fireworks display because that would have suited the players involved.

In doing so, Cummings has set the agenda for the independent inquiry that will belatedly start in spring next year –  and, conveniently for Johnson, is unlikely to report before the next general election. Cummings’ testimony will also loom large when the health and science committees publish their “lessons learned inquiry” before the summer recess, which Johnson cannot delay. Today’s dramatic evidence suggests their report will make uncomfortable reading for the prime minister.