David Cameron’s plans to open 500 new free schools by 2020 would “blow a giant £4 billion hole” in the government’s school buildings budget, a Cabinet member has claimed.

David Laws, the Liberal Democrat schools minister, has poured scorn on the prime minister’s proposals, claiming they would leave thousands of students in “crumbling classrooms”.

Mr Cameron today announced that a Conservative government would set up 500 free schools during the next Parliament, creating 270,000 new school places.

Speaking at a school in West London, the Tory leader said that free schools were twice as likely to be judged as “outstanding” by Ofsted. He also pointed to research published today by thinktank Policy Exchange which claims the schools are helping to improve poorly performing institutions nearby.

Mr Cameron also announced that 49 free schools had been approved in what will be the last wave of applications to go through before the general election.

But Mr Laws said his coalition colleague’s plans to build 500 new schools would lead to cuts elsewhere in the capital budget.

“Tory plans to build 500 new free schools would blow a giant £4 billion hole in the school buildings budget,” Mr Laws said. “This would condemn thousands more children to inadequate and crumbling classrooms, and jeopardise our efforts to ensure there are enough school places.”

The Lib Dem added that the education budget needed to be protected in “real terms” if new schools were to be built where they were most needed.

“The Tories have already set out plans to decimate budgets for schools, nurseries and colleges - now they are admitting capital budgets would be under attack under a majority Conservative government as well,” he said. “You simply can’t build a world-class system of education unless it is properly funded.”

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‘Free schools are part of the solution to ease pressure on places, not the problem’ - 14 January 2015