The “tide is retreating” for all-boys’ schools, the headmaster of an independent school has predicted.

Guy Sanderson, who leads Eltham College in southeast London, is reported in the Sunday Times as saying that boys need exposure to girls in order to receive a rounded education.

His school, which opened as a boys’ school in 1842 for the sons of missionaries, will start taking girls at the ages of 7 and 11 from 2020. At present, girls can enter the school only in the sixth form.

According to the Sunday Times, Mr Sanderson said: “The tide is definitely retreating for boys’ schools.

“If we want to prepare students properly for the future, this is the best way of doing it.”

Mr Sanderson also reportedly said he hoped the change would mean that boys noticed more quickly than he had done that girls can be highly intelligent - he only realised this himself when he was 22 and met his wife, a Cambridge graduate who is a senior City executive.