£22,350 cost of a place at Harrow

Boarding fees at Harrow School have gone from about £18,300 a year to £22,350 in four years.

Head Barnaby Lenon said the ISC was right to attribute part of the fall in families going private to a drop in the birth rate.

But he stressed that schools also have to be careful not to price out parents. "If fees go up too high or too fast, then an increasing proportion of parents will be unable to send their children to independent schools," he said.

A record rise of 10 per cent occurred last year, when private schools had to cover higher national insurance and teachers' salary and pension costs, said Mr Lenon.

He added that he had not noticed the sudden rise in visa charges hitting overseas parents. This year, he had received 780 applications for 160 places.