Most primary school children sit more than 30 tests before they leave at 11, according to a new survey. The brightest pupils take more than 40.

Colin Richards, professor of education at St Martin’s College, Cumbria, and a former primary HMI, has calculated that children must now take at least 19 test papers as part of the national curriculum key stage tests. Those sitting optional tests in the years in between - now taken by 90 per cent of schools - will sit 34 tests or assessments. For brighter pupils, who can sit extension papers in English, maths and science, the figure can rise to 43.

Professor Richards said: “I have been staggered by doing this count. In terms of official assessment our children are by far the most heavily assessed in the world. No other country has such a testing regime.”

Most seven-year-olds have to sit tests in reading, comprehension, writing, spelling and a 40-minute maths paper. The typical 11-year-old spends more than five hours on tests covering English, maths and science. The most able children in the top set can spend another two hours on extension papers.

“What must it be like for low-performing children to be given 19 or even 34 official reminders of their performance?” asked Professor Richards.

The time spent preparing for tests also worries Professor Richards. Optional tests are to be introduced for 12 and 13-year-olds. If schools use them as they have used those for eight, nine and ten-year-olds, he calculates, by the age of 14, pupils will in fture have spent almost two years of their English and maths teaching time on preparing for papers.

“Assuming that teachers in primary and the early years of secondary spend half a term revising for so-called optional tests and a term preparing for the key stage tests, pupils will spend the equivalent of 5.5 terms worth of teaching time on English and maths revising ,” he said.

The increase in time spent on testing has alarmed the National Association of Head Teachers. According to David Hart, its general secretary, schools are now moving towards annual assessment.

“We are in favour of testing children when they arrive at school and at seven and 11, but we are now in danger of becoming the most over-tested nation in the world,” he said.

Mary James of Cambridge University’s school of education said the the balance between the time spent on testing and other activities had begun to tip in the wrong direction.

“I suppose a certain amount of testing is a necessary evil. The problem is the balance,” she said.

However, a spokesman for the Qualifications and Assessment Authority denied the testing burden was too heavy. He said teachers had requested the optional tests to allow them to track pupils’ performance between key stage assessments. And they had simply replaced exams that would have taken place anyway.

He said: “There is no testing overload. The optional tests merely substituted for tests set by teachers themselves.

“Pupils benefit from a standardised system: teachers get invaluable information about the attainment of pupils, which can be used to raise standards.”