Ofsted's lawyers argued the segregation left girls "unprepared for life in modern Britain" [...]
May I make a contribution to this discussion from a rather different perspective and tradition and time?
I was born during WW2 and grew up in the East Midlands in a Roman Catholic working-class family. Apart from my mother, my family was all male.
My primary school was the local RC primary school. In this school boys and girls were treated differently - girls were protected, boys were treated as if they were inherently problematic (remember the old rhyme -
sugar and spice and all things nice .... slugs and snails and puppy dogs' tails?) One event I recall was a sudden rainstorm shortly before the afternoon session began. The girls were let into the school, the boys left outside in the playground. This was typical of the difference in treatment.
The messages from the pulpit - as far as a growing boy could deduce - contrasted the virtues of girls with the vices of boys. And when I became an adolescent I noted in these messages an implication that the virtues of young women were special and should be respected. By this time I had moved to the boys' grammar school and had little day-to-day contact with girls. My school had lessons on Saturday mornings and compulsory attendance at sporting fixtures on Saturday afternoons meant that weekends were girl contact free as well.
I left school having had little contact with girls, having little reliable information about the motivations, interests and behaviour of young women. It took me a considerable time to acquire the self-confidence to show an interest in close friendships with girls. I had been conditioned to regard my (hetero)sexuality with caution and to respect virginity. In retrospect, the period of my life which should have been an adventure was sterile, painful and empty.
The prevention of normal socialisation of boys and girls by means of physical, moral and educational segregation should be seen as totally unacceptable. And allowing this segregation to be driven by philosophical values derived from fairy and folk tales from another millennium is unforgivable.