State schools are turning out “too many amoral children”, because of the pressures of the results-driven culture, a leading prep-school headmaster is due to say today.

Richard Walden, chair of the Independent Schools Association, will say in a speech that some state schools are so focused on exams that they do not have time to teach children basic values.

The private school head, whose own school, Castle House School in Shropshire, charges up to £6,867 a year in fees, will say: “Schools are turning out too many amoral children because teachers cannot find the time to teach the difference between right and wrong.

“Too many staff are overwhelmed by the pressure to achieve results. It seems that the only results that matter are those which have created added value in terms of raising a pupil’s statistical level from one stage to the next, and parents are increasingly buying in to this notion.

“This focus on league tables and attainment levels distracts teachers and effectively disables them from providing children with a more rounded and enriching education - one that will give them the moral compass they need for life.”

He will add that independent schools devoted “a great deal of time” to extracurricular activities and their teachers strove “to provide pupils with emotional intelligence, a developed moral understanding and a willingness to make a contribution to society”.

But headteachers’ leaders in the state sector said Mr Walden’s belief that state schools were failing to teach morality was “blatantly untrue”.

Russell Hobby, general secretary of the National Association of Head Teachers, said: “It’s not just about the extra time you spend on extracurricular activities, it’s the way you teach, the behaviour policy and the code of conduct. It doesn’t depend on curriculum time.”

He added that it was interesting to note that a large percentage of independently-educated people dominated professions “not known for their morality”, such as banking or politics.

Mr Walden will also use the speech to his association’s annual conference in Coventry to back calls to introduce more publicly-funded independent school places in a bid to offer a broader education to more children.

The head, whose organisation represents 345 private schools, will say if politicians “had the courage” they would channel funds into placing pupils into well-established private schools.

This would help to solve the shortage of school places with less risk and cost to the government, he will say.

He will speak only a week after it emerged education secretary Michael Gove had raided the fund for solving the school places crisis to plug a £400 million hole in the free-school budget.

Mr Walden will add: “Independent schools devote a great deal of time to the extracurricular - to lessons and activities that enrich a child’s education.

“Our teachers strive to provide pupils with emotional intelligence, a developed moral understanding and a willingness to make a contribution to society.

“These are not measurable by statistics or on inspectors’ tick-charts, but they are the qualities that employers want.”