Boris Johnson and his ministers are too busy “covering their own backs” to properly counter the threat posed by the Indian coronavirus variant, Labour leader Sir Keir Starmer claimed.

Following Dominic Cummings’ explosive evidence about the Prime Minister’s handling of the pandemic, Sir Keir said “mistakes are being repeated” as the Government considers whether to further ease restrictions.

“Weak, slow decisions on border policy let the Indian variant take hold,” he said.

“Lack of self-isolation support and confused local guidance failed to contain it.

“We all want to unlock on June 21 but the single biggest threat to that is the Government’s incompetence.”

Writing in the Observer, Sir Keir said Mr Johnson’s reluctance to impose a second lockdown in autumn last year meant “avoidable and unforgivable” deaths in the second wave of the virus.

“The first wave we faced an unprecedented crisis. Decision making was undoubtedly difficult. Mistakes were inevitable. And the British public understand that.

“But by the summer, we knew much more about the virus.

“The Prime Minister was warned to prepare for a second wave. He did not do so. And over twice as many people died in the second wave than in the first.”

Mr Cummings, the Prime Minister’s former adviser, told MPs on Wednesday that “tens of thousands” had died unnecessarily because of the Government’s handling of the pandemic and accused Health Secretary Matt Hancock of lying about testing for care home residents discharged from hospital – a claim he denied.

Sir Keir said the situation in care homes had been a “betrayal”, adding: “We may never know whether Boris Johnson said Covid ‘was only killing 80-year olds’ when he delayed a second lockdown.

“What we do know is that the man charged with keeping them safe showed callous disregard for our elderly, as he overlooked the incompetence of his Health Secretary.”