Independent schools are withdrawing weaker pupils from GCSE and A-level examinations to inflate their league table position, teachers’ leaders claim.

In an act known as “soft culling”, schools that charge thousands of pounds a term in fees stand accused of persuading children not to take exams if they are unlikely to get top grades.

Others are even entering their least-able pupils for exams as private candidates so that their results do not appear on the school’s own results.

Geoffrey Boult, the chairman of the Boarding Schools’ Association, said that head teachers could be put under heavy pressure from governors to withdraw less able candidates from exams.

“I’m sure it’s been happening for years. It would be easy to say, if pupil X is not very good at a subject, don’t put him in for it. The danger is that you stop pupils from even taking a subject in the first place,” he said. Mr Boult, who is headmaster of the £23,000-a-year Giggleswick School in North Yorkshire, added: “It has probably happened at my school, but very rarely. We might say to a pupil, concentrate on the subjects you are good at.”

Although the school would not withdraw a candidate purely because of league tables, teachers would be well aware that such a move would boost their league table position, he added.

State schools have long been accused of steering less able pupils away from subjects perceived as difficult, such as science and modern foreign languages, in favour of softer subjects such as media studies and sociology to help to boost their league table results and meet government targets.

But the independent sector has been less willing to admit that they are so influenced by league tables.

John Dunford, general secretary of the Association of School and College Leaders, said that he had no doubts that soft culling went on in independent schools.

“It is one of the effects of using the wrong performance measures of school performance. Schools should be judged by the progress made by their students, not by the number of grade As they produce,” he said.

Barnaby Lenon, the headmaster of £26,000 a year Harrow School in North London, told The Times Educational Supplement that some schools entered pupils privately so that they did not show up on their school results.

“I think it is absolutely dreadful and is a reflection of the exam-driven culture which afflicts some schools anxious to retain their place in the league tables,” he said.

Graham Able, the headmaster of Dulwich College in South London, said that he would be surprised if any of the most academically selective schools engaged in the practice, but said that it may happen in middle-ranking schools.

“It would be most likely to happen in smaller schools, where changing the numbers of pupils entered for an exam would make a difference to the league table position and where there is strong competition from a neighbouring school that is close to it in the league table,” he said.

But Andrew Halls, the head of King’s College School in Wimbledon, South London, believes soft culling to be rare.

“There will be times when a pupil is completely sinking in an A-level class and we might say, ‘Why don’t you drop it; you don’t need a fourth A level?’.

“But the idea that we could say to a boy or a girl, ‘Don’t sit an exam because it will hurt our league table results’ is quite extraordinary,” he said.

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