The figures have prompted a call for greater investment in primary schools as infants settle in for another school year. Official Government records show that a Department of Education decision to relax legal limits on class sizes has had a dramatic impact on the region’s schools.

Over the last four years the number of pupils in classrooms above the previous 30-pupil limit has risen 186 per cent. One school in Leeds was revealed to have had 63 pupils in one primary school class, with the city overall seeing a 313 per cent increase in overcrowded classrooms.

North Yorkshire saw a 241 per cent increase, with 1,070 infants in classrooms which would previously have been limited. The changes came after the Government tweaked a previous Labour law which gave schools just one year to bring any overcrowded class down to a maximum of 30 pupils. Instead, schools can now take several years to try and tackle the move, a change introduced to cope with the impact of a rising birth rate.

Former Education Secretary David Blunkett said the figures showed the Government had its priorities wrong. The Sheffield Brightside MP said: “We have a situation in which, as we have learned, tens of thousands of youngsters in infants school are now in classes of over 30 at a time when the Government are spending £1 billion to subsidise free school meals for the most wealthy parents of those same infants.

“Is it not a paradox that they can get a free school and a free meal, but they cannot get a place in an infants school with a class size of fewer than 30?”

And Leeds North East MP Fabian Hamilton warned: “If the current trend in the growth of class sizes continues, it will be tragic for the educational prospects of our children, because within six years from now up to 450,000 young children could be in classes of over 30.”

Selby MP Nigel Adams has said the Labour Party has not always been so opposed to larger classrooms, pointing out that in 2008 a schools minister had told the teaching union, the Association of Teachers and Lecturers, that “it was perfectly acceptable to teach maths to pupils in class sizes of 70.”

Education experts have said the time has come for politicians to put aside their difference and focus on how best to educate children at a time of limited funds. The Education Foundation think tank has said the UK has to address the impact of rising birth numbers, rasing the issue at a recent summit attended by the Education Secretary Michael Gove.

Think tank co-founder Ty Goddard said that unless changes were made there would continue to be a rise in the number of schools forced to turn libraries into class rooms and other measures. Education minister Nick Gibb said: “Action has been taken by this Government to create more good school places and local authorities are delivering.

“We have already seen an increase of 260,000 school places between 2010 and 2013, including 212,000 primary places, with more than 300,000 primary places in the pipeline for delivery by September 2015.

“We are working closely with the local authorities across the country facing the greatest pressures to support them in ensuring that every child is offered a local school place.”