Labour leader Keir Starmer has accused Boris Johnson of ignoring his offer to help build a consensus around the reopening of schools in England.
Primary schools had been told by the government that they could re-admit pupils from certain year groups at the start of this week.
But more than two in five schools have not done so, according to the UK’s largest teaching union, the National Education Union (NEU).
Sir Keir said the prime minister had presided over a loss of public trust in his government, just when the coronavirus crisis meant it was needed most.
In heated clashes at Prime Minister’s Questions (PMQs), he said he had privately written to Mr Johnson two weeks ago offering to help him build a consensus that would allow teachers and parents to feel more confident about sending their children back to school, but had received no reply.
Mr Johnson responded that Sir Keir had not offered "any dissent" during a private phone call about the Government's approach to schools, a charge Labour denies.
In an increasingly fiery exchange, Mr Johnson also accused the Labour leader of making "endless attacks” on public trust and confidence.
The clash came just hours after a new YouGov poll suggested that a fifth of Britons are following lockdown rules less strictly than they were before, with a third citing Dominic Cummings as a factor.
The prime minister’s special adviser remains in post despite apparently breaching the rules by taking a 30 mile drive in county Durham while the rest of the country was being told to stay at home.
Labour sources later said there had been no one-on-one phone call between Mr Johnson and Sir Keir. They said there had been a telephone call with all the opposition leaders, in which the government’s position had been set out.
The Labour leader also published the text of the letter sent to Mr Johnson, saying the public could make up their own mind on how constructive he had been.
In the letter Sir Keir said he was willing to help but when it came to schools “we are not there yet”.
