Keir Starmer has accused Boris Johnson of causing a collapse in public confidence over the government’s handling of the coronavirus crisis, saying No 10 will be directly responsible if the infection rate starts to rise again. In an exclusive interview with the Guardian, the Labour leader launched a stinging attack on the the prime minister, accusing him of “winging it” over the easing of the lockdown and making an already “difficult situation 10 times worse”. He also questioned whether the timing of some decisions over the relaxation of the lockdown rules had been taken “to try to deflect attention away” from the Dominic Cummings affair – an episode, he said, that showed Johnson was too weak to sack his chief adviser. In a significant hardening of his language, Starmer said Johnson had to “get a grip” of the crisis. “My [worry] is that after a week or more of mismanagement, I’m deeply concerned the government has made a difficult situation 10 times worse,” he said. “We’ve called for an exit strategy. What we appear to have got is an exit without a strategy. We want to see society reopen, we want to see more children back at school, obviously people want to see their families and we want to see businesses open. “But like many people across the country, there is a growing concern the government is now winging it. At precisely the time when there should have been maximum trust in the government, confidence has collapsed,” he said. Starmer blamed the fall in public trust on the “Cummings factor, the sense of one rule for them and one rule for everyone else” – a referenceto the furore provoked when the Guardian revealed Johnson’s chief adviser had breached the lockdown. But he also cited “mismanagement” in the government’s sudden decision to lift shielding restrictions for 2.2 million people without advance notice for public health directors or GPs, and concerns about the test and trace system that councils do not believe will be ready until the end of the month at the earliest. In addition, the Labour leader said there had been a failure of leadership over the decision to get schools to reopen without consulting widely enough with unions, teachers and parents. “I am putting the prime minister on notice that he has got to get a grip and restore public confidence in the government’s handling of the epidemic … if we see a sharp rise in the R rate, the infection rate, or a swathe of local lockdowns, responsibility for that falls squarely at the door of No 10. “We all know the public have made huge sacrifices. This mismanagement of the last few weeks is the responsibility of the government.” Starmer’s intervention came on another difficult day for the government as it emerged that: The death toll surpassed 50,000 for the first time, according to official figures, 10 weeks after the nation went into lockdown. Prof Neil Ferguson, the leading epidemiologist who advised the government until he quit over breaking the lockdown rules, warned that coronavirus infections in hospitals and care homes are spilling into the community and sustaining the outbreak to the point that cases will remain steady until September. An inquiry found that people of black and Asian origin are disproportionately affected by coronavirus, leading to calls for the government to take action to protect these groups. The head of the UK Statistics Authority accused the government of continuing to mislead the public over the numbers of tests carried out for Covid-19. It emerged that England’s chief medical officer, Prof Chris Whitty, was responsible for vetoing the government’s wish for England’s official coronavirus alert level to be reduced, ruling that it should remain at four – meaning “transmission is high or rising exponentially”. No 10 said it would be cutting back its daily press conference to just weekdays to secure bigger television audiences. Speaking from his parliamentary offices, the Labour leader said he would continue to engage constructively with the government, defending his approach of not making criticism for its own sake. However, he said he had become increasingly concerned about mistakes made by Johnson’s administration in the last week. On Johnson’s handling of the Cummings furore, Starmer said Johnson’s plans to loosen restrictions were laid out as the government was in the grip of a crisis. Last Thursday, Johnson was under pressure to sack Cummings over revelations he had driven from London to his parents home in Durham during the height of the lockdown – and then taken a 60-mile round trip to a beauty spot to test his eyesight. “They obviously took a decision to try and deflect attention away from the Cummings affair,” Starmer said. “There are questions that the government needs to answer about the precise timing of the measures it put in place. “It’s blindingly obvious to me that the prime minister is just too weak to sack [Cummings].” Starmer added that this “loss of trust and confidence” was the “most troubling aspect of the whole Cummings affair”. “If you had said which is the week the government needed maximum trust and confidence, the answer is the week in which you start easing restrictions … that’s where you need maximum trust and confidence. That’s the thing the government has burned in the last few weeks,” he said. The Labour leader said he would now be asking for more meetings with Johnson, Mark Sedwill, the cabinet secretary, and Prof Chris Whitty, the chief medical adviser, to address his concerns about the mismanagement of the last few weeks. He also revealed he wrote a “private and confidential” letter to the prime minister two weeks ago offering to work constructively together to gain consensus for reopening schools, but Johnson has not replied.