The government’s plan for all primary schools in England to reopen before the end of summer has been scrapped.
Education secretary Gavin Williamson told the House of Commons on Tuesday that the ambition is no longer feasible.
Prime minister Boris Johnson had wanted all primary schools in England to reopen for four weeks before the summer break as part of his plan to ease the coronavirus lockdown.
The government has backed down on its plan in the face of widespread opposition from teachers, doctors and scientists.
Children in England began returning in a phased process last week, with reception, year 1 and year 6 pupils heading back first, although two in five primary schools did not reopen.
However, primary schools will now be given flexibility on whether or not they admit more pupils.
Some schools said they did not have enough space to admit all pupils in the eligible year groups, while adhering to government guidance to limit class sizes to 15 and encourage fewer interactions.
Williamson said the government would like to see schools who "have the capacity" bring back more pupils where possible before the summer break.
He told MPs the government was still working towards bringing all children back to school by September.
Figures released by the Department for Education (DfE) on Tuesday showed that just over half (52%) of primary schools in England had reopened to more children on Thursday last week.
But Williamson said this has since risen to more than 70% of primary schools in recent days.
He said that secondary schools will be able to provide some face-to-face support from 15 June for years 10 and 12.
Williamson said the government is prepared to shut “clusters” of schools if new COVID-19 cases emerge.
Shadow education secretary Rebecca Long-Bailey expressed her "deep dismay" over the government's handling of the plans for schools to reopen.
She told the Commons: "For weeks, headteachers, education unions, school staff and many parents have warned that the plans to open whole primary schools before the summer were simply impractical while implementing social distancing safely.
"If the government had brought together everyone involved in implementing these plans from the outset and really taken on board what they had to say, they would not be in the situation of having to roll back at all.”
Geoff Barton, general secretary of the Association of School and College Leaders, said he was not surprised the plan had been dropped.
"The 'ambition' to bring back all primary year groups for a month before the end of the summer term was a case of the government over-promising something that wasn't deliverable,” he said.
"It isn't possible to do that while maintaining small class sizes and social bubbles, so we aren't surprised that the policy has been jettisoned."
Paul Whiteman, general secretary of school leaders' union NAHT, said there would have been "significant practical barriers" to bringing all primary pupils back in the summer term if the goal had gone ahead.
He said: "With the end of term just six weeks away, government now needs to provide urgent clarity on the anticipated constraints that schools may face in September, so that schools and parents can start to look ahead and plan with greater understanding of the possible disruption that may yet still follow."
Ian Robinson, chief executive of the Oak Partnership Trust, which runs three primary schools and a special school in Taunton, Somerset, told BBC Radio 4's Today programme on Tuesday: "It demonstrates that the secretary of state and the Department for Education are listening to the profession – I believe they have listened to the profession and this is a really positive step forward.
“From my own trust's point of view, it is all about simple practicalities, it is not about whether you want children in schools or not.
"We simply don't have enough physical space for any more year groups and we don't have any more human resources for any more year groups."
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But Anne Longfield, the Children's Commissioner for England, told BBC Breakfast: "I think it's a huge disappointment for those children who'd expected to go back into school before the summer now now may not.
"It does mean that the vast majority, probably about eight million children, very likely won't return to the classroom until September, which means that, again, there will be a huge variation in their learning over that period.
“We've got some children, more affluent children, especially those going to private schools, who are literally attending zoom schools from nine till three in the afternoon with lessons as normal.
"And we know that 90% of disadvantaged children aren't going online for more than two hours, if that.”
She said children will remain "isolated", with many living in "fragile" family environments.
It comes after health secretary Matt Hancock conceded on Monday that secondary schools in England may not fully reopen until later than September.
Hancock said at the Downing Street briefing that it was still "our current working plan" that secondary schools in England will not open until September "at the earliest".
Hancock has also unveiled plans for pupils and teachers across England to receive coronavirus testing to monitor the spread of the disease as classes resume.
With approval from parents and guardians, children will be tested to see whether they have COVID-19 or have had an infection in the past under the surveillance programme.
Hancock is aiming to have up to 100 schools tested across England by the end of the summer term, with around 200 staff and children involved at each of those schools.
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