• Video report by ITV News Science Editor Tom Clarke

Sir Keir Starmer has claimed the government's decision to abandon Covid-19 contact tracing early on in the coronavirus crisis left a "huge hole" in the UK's defences.

At a tense and combative PMQs the Labour leader levelled stinging criticism at Boris Johnson, saying for "nearly ten weeks in a critical period" the UK has been "without effective tracing".

He compared the UK's death toll of at least 35,000, where there is no tracking and tracing in place, to that of Germany and South Korea - around 8,000 and 300 deaths respectively - which both implemented tracing early on.

Responding, the prime minister claimed "vast progress" was being made on tracking and tracing and said he had "great confidence" that by June 1 a system would be in place.

He said the government will have recruited 25,000 staff capable of tracing the contacts of up to 10,000 new Covid-19 cases a day by June.

Sir Keir said there is "no getting away from" the decision on "March 12 when tracing was abandoned".

Prime Minister Johnson was visibly rattled by Sir Keir's line of questioning, saying it was "peculiar" for the Labour leader to ask about testing and tracing, saying he is "perfectly aware" of the situation.

He said Sir Keir's "feigned ignorance doesn't come off very well", as he announced the time table for the test-and-trace operation.

The PM also announced at least 181 NHS staff had died during the crisis and 131 social care workers.

Sir Keir criticised the government's record on care homes, with more than 10,000 care home residents dead, he questioned a claim made by the health secretary that a "protective ring was thrown around care homes from start".

He said that claim was “flatly contradicted” by the chief executive of care England on Tuesday.

Sir Keir, quoting Professor Martin Green, said "we should have been focusing on care homes from the start, despite what is being said, there were cases of people who didn’t have a Covid status, or were symptomatic, who were discharged into our care homes".

The government advice to hospitals from the April 2 to April 15 was "negative tests are not required prior to transfers/admissions into the care home."

“What’s protective about that?” Sir Keir asked the prime minister.

Mr Johnson said his opposite number was "right to draw attention to what has happened in our care homes" but added "no one was discharged into a care home this year without the express authorisation of a clinician".

The PM claimed Sir Keir was "in ignorance of the facts" around coronavirus testing in care homes after the Labour leader cited a government command paper which said "every care home for the over 65s will have been offered testing for residents and staff by the 6th of June".

"That’s over two weeks away," Sir Keir said as he asked: "What’s causing the continued delay in routine testing in our care homes?"

Mr Johnson responded: "We are absolutely confident that we will be able to increase testing.

"We will get up to 200,000 tests in this country by the end of this month.

"This county is testing more than virtually any other county in Europe."

Meanwhile, Commons Speaker Lindsay Hoyle told Health Secretary Matt Hancock off for heckling the opposite bench in the Commons chamber, saying he would be “more than happy” for him to leave and be replaced with someone else.