Private schools have become “overly focused on exams and league tables, to the exclusion of much else,” one of England’s leading independent school headteachers has claimed.

Sir Anthony Seldon, the outgoing Master of Wellington College in Berkshire, believes that, as a result, originality has been squeezed out of the sector.

In his last speech-day adress on Saturday, before he leaves to become vice-chancellor of the University of Buckingham, Sir Anthony plans to attack the adverse effect that government policies and an obsession with exam results have had on private schooling.

“The tyranny of league tables and a succession of government policies…have forced up costs and limited the range of outlets,” Sir Anthony will say. “Private schools, in their hunt for exam-focused parents from Britain and abroad, have narrowed their range of educational opportunities and become overly focused on exams and league-table performance, to the exclusion of much else.”

The master of the £11,375-a-term boarding school will insist that the pressure placed on current pupils is “totally unacceptable”.

“I am deeply concerned for our children, whose experience of education is now so exam-heavy, and whose preparation for life and the workplace is so light,” Sir Anthony will say.

He will then call on independent headteachers to unite and put pressure on the government to allow their schools the freedom to provide a more thorough, rounded education to pupils.

“A principal justification for an independent sector in education is that it uses its independence to be innovative in ways that challenge and provoke the large state sector,” he will say.

“But the crushing burdens of state requirements, league tables and inspection regimes, have squeezed the lifeblood and originality out of much of the sector.  One independent school now looks much like another.

“We lack the force, individually and collectively, to challenge the monolithic state regime in education.”

But Sir Anthony’s claims were questioned by Barnaby Lenon, chairman of the Independent Schools Council.

“There is no evidence for most of Anthony Seldon’s claims,” he said. “There is huge diversity and innovation happening across the UK independent sector. Our exam results are excellent but research shows that parents choose our schools mainly because of the holistic and broad education on offer. It is not the case that independent schools are chasing league-table positions - most now offer IGCSEs which have the effect of excluding them from the Department for Education league tables - and many of the highest achieving independent schools refuse to release their exam results to the press.”

Mr Lenon added: “Our very independence from government control means our schools provide the bespoke education that local parents are seeking for their children.”