It comes as family members of people who died during the pandemic hit out at his admission the government “underestimated” the threat of coronavirus.
Appearing at the Covid-19 Inquiry in London on Wednesday, Mr Johnson apologised for “the pain and the loss and the suffering of the Covid victims” but said he was “not sure” whether Government decision-making had led to “materially” a larger number of excess deaths.
Jane Basham, 61, whose sister Sandra died in January 2021 after contracting coronavirus, branded Mr Johnson’s apology “meaningless”, adding she held him responsible for her sibling’s death aged 61.
Sandra Basham had been caring for older people in their homes near Dartford, Kent, during the pandemic before she was admitted to hospital, with Ms Basham adding her family did not see her because they were taking the virus seriously.
(Boris Johnson) ignored the science, showing utter disregard for people’s lives
Ms Basham, of Ipswich, Suffolk, said: “His apology is meaningless to me, and many of us who are bereaved.
“If Boris Johnson was truly sorry then he would have delivered a public inquiry when it was first requested and not forced a group of traumatised bereaved relatives to have to fight for it.
“He would have shown humility and met the bereaved families who stand outside the inquiry every day rather than scuttling in before dawn.”
She added: “We didn’t know it then, but Sandra was doomed from the moment he dragged his heels on the second lockdown – he knew precisely how serious it was by then so there’s no excuses.”
“He ignored the science, showing utter disregard for people’s lives.”
“I hold him responsible for Sandra’s death.”
Mert Dogus, 21, whose father died of Covid, told PA that Mr Johnson “should be giving answers for some of his actions” at the Covid inquiry.
His father, cab driver Haci Ali Dogus, 49, died in March 2020, leaving behind his wife and two sons.
In response to Mr Johnson’s apology for the “suffering of the Covid victims”, Mr Dogus, a student at Brunel University London, said “I’m not surprised, he kind of owes it.
“Obviously, he was in control of the country at the time, so naturally, he should be apologising for those who are lost.”
Mr Johnson admitted he should have "twigged much sooner" about the threat posed by Covid-19 in the early days of the pandemic, as he apologised for "the pain and the loss and the suffering" of its victims.
The former prime minister's highly anticipated evidence to the UK Covid-19 Inquiry, which was hit by protests, also saw him defending the culture of his No 10 after other witnesses branded it "toxic".
He rejected accusations he had shown poor leadership by oscillating over whether to back tough restrictions in the early months of 2020.
Former aides have blamed Mr Johnson's tendency to veer on key decisions in March of that year for delaying the lockdown.
But he argued it was his job to "test" the "completely novel policy", adding: "It matters to the livelihoods of people up and down the land. I had to go through the arguments and that is what I was doing."
Challenged over the slow response to the unfolding crisis, Mr Johnson said Whitehall "underestimated" the need for action, adding that it was only when he saw the "horrors" of the outbreak in Italy that he realised the seriousness of the virus.
He suggested the experience of previous diseases such as Sars, Mers and swine flu clouded officials' judgment while a coronavirus pandemic was "outside our living experience".
Mr Johnson said: "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.
"But I think it'd be fair to say that the scientific community within Whitehall at that stage was not telling us that - I was not being informed that - this was something that was going to require urgent and immediate action."
The ex-premier said his government "might have operated differently" if it had believed some of the early forecasts that were being made about Covid-19, but was unable "to comprehend the implications".
"I think collectively in Whitehall there was not a sufficient loud enough klaxon of alarm."
The former Tory leader defended his eventual decision to order England's first lockdown on March 23 2020, saying by the middle of that month he was giving arguments against restrictions "pretty short shrift".
"I no longer had the luxury of waiting. It was over," he told Baroness Heather Hallett's probe.
Mr Johnson appeared to become emotional as he discussed his "anxiety" about possible behavioural fatigue if he imposed a lockdown too early without a vaccination programme.
He looked on the verge of tears as he described 2020 as a "tragic, tragic" year.