This sum, pound;50.57 million - to be spent on key stage 1, 2 and 3 tests - would pay the annual salaries of more than 2,500 new teachers.

David Laws, Liberal Democrat spokesman for children, schools and families, who was given the figure in a written parliamentary answer, said: “This is a staggering amount of money to spend on testing, rather than education. It raises the question, is the testing regime giving value for money?”

The full cost of testing could be even higher, he said, once other elements, such as teachers’ time, were taken into account.

Professor Peter Tymms, of Durham University, who has questioned the accuracy of test results, said: “This is a lot of money. Where’s the evidence that it’s having a positive effect?”

But Jim Knight, schools minister, said it was “money well spent”. “Seeing that children leave school up to the right standard is the highest priority of government,” he said.

Mr Laws also uncovered “astonishing levels” of spending on rail travel by department officials and on conference hire by the Qualifications and Curriculum Authority.

Some pound;4 million was spent on first-class train travel and pound;4.2 million was spent on hiring meeting rooms in the past 18 months. Many luxury hotels were used to host conferences organised as part of the secondary curriculum review.

A QCA spokesman said the review was a major undertaking and that it had spoken to 8,500 teachers, local authority officials, parents, governors and pupils as part of the consultations.