Many primary schools are spending too long drilling children to pass national tests and are neglecting to give them a proper grounding in the core subjects of English, maths and science, the government’s examinations watchdog warned.

Ken Boston, chief executive of the Qualifications and Curriculum Authority, said only better teaching, which focuses on individual children and learning, will improve results.

Dr Boston added: “In many schools too much teaching time is taken up with practice tests and preparing for the Key Stage tests in English, mathematics and science, at the expense of actual teaching in these core subjects and other areas of the curriculum.”

Schoolchildren in England are the most tested in the world. They sit national curriculum tests at Key Stages 1 (aged 7), 2 (aged 11) and 3 (aged 14).

Because the Key Stage 2 test results form the basis of school league tables, some devote months of teaching time to prepare children, resulting in a narrow curriculum.

Dr Boston did not accept that the solution was simply to abolish the tests. He insisted that the national curriculum or “SATs” tests, were appropriate for measuring how children perform. He has previously suggested that key stage testing of whole year groups should be replaced by random testing and teacher assessments that measure individual pupil progress. But the Government has ruled this out.

Dr Boston’s latest remarks came as pupils await GCSE, A-level and national test results over the next two weeks.

His views are at odds with those of ministers, who claimed that setting targets for the percentage of pupils they want to see passing the tests had “galvanised” schools into action. Lord Adonis, minister for schools, claimed that national tests for 11 year olds “take up precisely 0.14 per cent of Key Stage 2 teaching time”. This figure refers to the time taken to sit the test.

Times recommends

• Screen tests are the future of exams
• No more free boarding schools for diplomats
• Popular Jewish School broke race laws