Boris Johnson has admitted that there were decisions that his government “could and should have” made to stop the spread of coronavirus but denied he had made major mistakes and attempted to defend the chaotic and abusive culture in his top team. In his long-anticipated evidence to the official Covid inquiry, the former prime minister even insisted that a Downing Street culture widely described as toxic and dysfunctional in fact led to better decisions. In a full day of questioning by the inquiry’s lead counsel, Hugo Keith KC, Johnson frequently said he couldn’t recall meetings or what he had been told by his ministers and advisers. In a version of events described as “deluded” by one bereaved relative watching in the room, Johnson rejected yet more evidence of bitter internal warfare involving officials, notably his then chief adviser, Dominic Cummings. While conceding some errors over the outbreak of the virus, saying there were “clearly things we could and should have done if we had known and understood how fast it was spreading”, Johnson insisted these lessons were only apparent in retrospect. He faces Keith for a second session on Thursday, when he will be challenged over delays to locking down the country for a second time, ahead of Rishi Sunak’s appearance next week. While much of the evidence involved failings that had already been mentioned by other witnesses in recent weeks, the extent of the turmoil, indecision and toxic culture overseen by Johnson was laid bare. The hearing was shown an exchange of WhatsApp messages from May 2020 between Mark Sedwill, the departing cabinet secretary, and Simon Case, who was to replace him. Sedwill said he had only agreed to stay temporarily in the job – the most senior civil service role in the UK – after Johnson gave him guarantees about “behaviour” from others. In response, Case said he would only stay in No 10 if he had similar guarantees, adding: “I will work for you and the PM. I will not work for Dom.” Shown the messages and reminded of earlier evidence about a sometimes abusive and combative environment in Downing Street, Johnson insisted that he had never seen the worst of this, but also that it had been a net benefit to the nation. “I don’t think it was a bad thing to have people who were willing to challenge the consensus and get things done, and whatever you may say about the government, it did get an awful lot of things done,” Johnson said. “We needed to have an atmosphere in which people were able to say things that were controversial at the time.” Johnson accepted that Cummings – who he did not refer to by name – had proved problematic, but even here he argued that this had positives. “I knew that some people were difficult. I didn’t know how difficult they were, clearly,” he said. “But I thought it was better on the whole for the country to have a disputatious culture in No 10 than one that was quietly acquiescent to whatever I, or the scientists, said.” Johnson’s evidence to an inquiry that he set up himself in 2021 saw him arrive at the venue in west London three hours before the session began, avoiding the bulk of protesters who had gathered outside. As he began speaking, the Covid inquiry chair, Heather Hallett, had to briefly interrupt proceedings so that ushers could remove four people in the public seats who were holding up a sign reading, “The dead can’t hear your apologies.” Johnson had just begun to say he was sorry “for the pain and the loss and the suffering of the Covid victims”, but under questioning from Keith, it became apparent that his remorse did not mean he felt he could have handled the pandemic better. Asked by Keith whether an acceptance of error meant that avoidable mistakes had happened, or just that with hindsight some things could have been done differently, Johnson said: “I can’t give you the answer to that question. I’m not sure.” Under more detailed questioning about the lead-up to the pandemic, Johnson repeatedly denied any personal culpability, beyond expressing the retrospective wish that he had challenged scientists more keenly over an earlier lockdown. Asked why he had not acted more urgently in January and early February 2020, amid warnings that Covid was spreading fast, Johnson portrayed himself as at the mercy of a government-wide mindset of understandable complacency, given that earlier viruses such as Sars and Mers had fizzled out. “When you read that an Asiatic pandemic is about to sweep the world, you think you’ve heard it before, and that was the problem,” he said. “I was not being informed that this was something that would require urgent and immediate action.” He added: “I think it would certainly be fair to say of me, the entire Whitehall establishment, scientific community included, our advisers included, that we underestimated the scale and the pace of the challenge ... We should collectively have twigged much sooner. I should have twigged.” However, by 23 March, when the lockdown was imposed, Johnson said there was no other option. “We’d run out of wiggle room,” he said. “I no longer had the luxury of waiting. It was over.” Yvonne Fryer, who lost her husband, Miltos Petridis, 58, in April 2020 and watched Johnson from inside the inquiry room, said he appeared “deluded”. “He didn’t come across as someone with more expertise or a better understanding of events than the rest of us,” she said. “He wasn’t up to the job.” Lobby Akinnola, a spokesperson for the Covid-19 Bereaved Families for Justice group, which represents about 7,000 families, said the evidence had been “worse than what the bereaved families feared was happening at the time”. “Back then, we were often criticised for being unfair on the government when we raised concerns,” he said. “It’s clear now we weren’t being anywhere near critical enough.”