'Russell Hobby, general secretary of the National Association of Head Teachers, said an over-reliance on league tables risked causing “unseen damage” to the education system.

In a blistering attack on the Coalition, he said children were increasingly being drilled to pass high-stakes tests at the expense of promoting a love of reading, understanding how language works and putting numeracy to practical use.

The comments – in a speech to the NAHT’s annual conference in Brighton – came as the union proposed a wave of industrial action in protest over Government reforms.'

Read more: Schoolchildren 'Being Turned into Statistical Fodder'