Boris Johnson has insisted that all pupils should be back in school by September to help the economy recover from the coronavirus crisis.
As hopes of a swift, v-shaped recovery fade, the prime minister said re-opening schools would help get the economy 'moving again'.
The prime minister’s comments put him on a potential collision course with teaching unions, who have warned his government to prepare a Plan B.
Earlier this week scientists warned current levels of testing and contact tracing were inadequate to prevent a second wave of coronavirus after schools re-open.
Even as Mr Johnson hailed the service as "world beating" today, new figures show that thousands of people are still not being reached.
Rupert Soames, the head of Serco, which employs thousands of contact tracers, also admitted that one in five contacts may never be traced.
On a visit to Warrington, Mr Johnson said it was “very, very important" that schools re-open at the start of September and "we... get all the pupils back into their schools. That will be also very, very important for getting our economy overall moving again."
The prime minister also claimed there were "real signs of strength in the UK economy".
But ministers fear too few workers are following government advice, designed to help stimulate the economy, to return to work if they can.
The move was designed to be a step on path to Mr Johnson’s hopes of a return to ‘significant normality’ by Christmas.
But there are signs many people are continuing to stay at home, where they spend less money.
Robert Jenrick, the housing secretary, also issued a call for Londoners to return to their offices and spend in shops and restaurants to save thousands of jobs.
The move would “support the economy” he said.
His call came as the Bank of England warned that the UK’s economic recovery would be slower than initially hoped, killing off any expectation of a V-shaped recovery.
The downturn will not be as deep as initially predicted, the bank forecast.
But there would still be a jump in unemployment, to 7.5 per cent at the end of this year, leaving a total of 2.5 million people out of work, the highest figure since 2013.
Schools risk becoming the latest battlefield in the war over whether the government should prioritise protecting health or protecting the economy.
Earlier this week Avis Gilmore, deputy general secretary of the National Education Union, said that in order to open schools safely a robust test, track and trace system was necessary as well as a “Plan B in place should any regional or national spikes occur”.
But the Children’s Commissioner for England has warned classrooms must be the last places to close after all other options, including pubs, if there's a second wave of coronavirus.