Hundreds of thousands of pupils could end up with less room to play outside because a squeeze on school places has meant classrooms are being built on playgrounds and playing fields, it has been reported.
Information on school expansions from 82 local authorities suggests that just over a third (35%) of primary schools that have grown or are due to grow in size will end up with less outdoor space for youngsters, according to an investigation by the Times Educational Supplement (TES).
A further 54% are not due to lose space, but will have more pupils using the same area.
The figures come amid a continuing concern about a squeeze on school places, particularly for primary-age children, that has been fuelled in part by a rising birth rate.
Last year, a study by the National Audit Office (NAO) warned that by September 2014 an estimated extra 256,000 primary and secondary school places will be needed to meet demand. Of these, 240,000 are required in primary schools, with more than a third (37%) needed in London alone.
Around £5 billion of funding is being made available to councils to create new school places, the Department for Education (DfE) has previously said, and around 212,000 new primary places were created between May 2010 and May last year.
The investigation found that of the 957 expanding primaries it received information about, around 335 are losing outdoor space and a further 520 are not losing space, but will have more pupils in the same area.
This would mean, based on an average primary school size of 250 youngsters, that there would be less space per child for 213,750 existing pupils, the TES calculated.
The figures also show that 102 schools are gaining space.
David Burchett, operations manager for the Learning through Landscapes play charity, told the magazine that access to outside space was "incredibly important".
"Children need space. We appreciate that some schools are on restricted sites, but they should do whatever they can," he said.
"It would be unacceptable to say 'Right, let's fit 60 children into a classroom where there's room for 30'."
A DfE spokesman said: " We have brought in new regulations to make it harder for councils and schools to build new classrooms on their playing fields.
"They must apply directly to us for permission and our rules make clear that this should only be a last resort where there is a pressing need for new school places. We consider each case on its merits and permission will only be given if councils and schools satisfy us that suitable space is available so children can still play outside."