In his speech to the BSA's annual conference in Brighton, later today, leading headmaster Christian Heinrich will say that long school hours offer a "wider co-curriculum alongside the extended core of academic subjects".
He will add that children should be given a greater chance to develop the qualities that "hold together society". He will say:
The qualities that suggest there is more to society than just the individual and family. Children and young adults learn about sharing and borrowing, about others' feelings, concerns and priorities, about self-control and perseverance and, perhaps most importantly, about curiosity, in an environment in which it is possible and much encouraged to learn safely from your mistakes rather than to repeat them.
So I exhort children at my school: 'Climb trees! Cook your own lunch! Drive a go-kart around the car-park (cordoned off!). Even play poker!'. There's more to school than classrooms and exams. Make mistakes whilst the consequences can be managed and the lessons learned.