Later that evening, in the windowless lecture room GC1-08, which juts out silver and angular over north London’s Holloway Road, the members of the Islamic Society file in. Through a side door come the men, occupying the seats at the front. Through another door come the women, sitting as far back as possible. There are no signs in place, and the society insists it has no policy of segregation, and yet on more than one occasion, a female late arrival is directed to sit at the back.