A quarter of them also had to retake the numeracy test – up from 19 per cent in 2000 – while 13 per cent needed at least three attempts before they managed to pass a counting test.

The simple literacy test, which last year asked trainees to spell the words ‘following’, ‘formally’, ‘preference’ and ‘acknowledge’, had to be retaken by one in five would-be teachers, which was more than three times the failure rate back in 2000.

Yesterday Michael Gove, the Shadow Schools Secretary, pledged that a future Conservative government would raise teaching standards.

He said: “It is vital children have the best teachers available. It is very worrying that so many more trainees are having to repeat these tests. We want the most talented people to be encouraged to enter the profession.

“We want a new generation of maths and science teachers in primary school and secondary school. At the moment, trainee teachers can re-sit the basic literacy and numeracy tests, which are the gateway to the profession, an infinite number of times.