A long-running legal battle between Ofsted and the Al-Hijrah Islamic state school in Birmingham has reached the Court of Appeal. The principle at stake is whether segregating boys and girls - for all classes, breaks and trips - amounts to unlawful sex discrimination in a mixed-sex setting. Ofsted's lawyers argue that it is "a kind of apartheid", leaving girls "unprepared for life in modern Britain". The school maintains that gender segregation is one of its defining characteristics and that the policy is clear - parents can make an informed choice. The case is based on the Equality Act, which means the implications of the ruling will be far-reaching and will apply to all schools, not just state schools. Should gender segregation be allowed in co-educational faith schools? If it is as abhorrent as segregating children according to their race, why is the great British tradition of single-sex education not the subject of similar scrutiny? The case also raises wider moral concerns about what we as a society will allow to go on in faith schools, whether they are publicly-funded or not. Is the promotion of one dominant world view - taught as "truth" - desirable? Are faith schools a vital component of multiculturalism or a threat to it? Should a truly integrated society be judged on the diversity within its schools, lest they become cultural or religious ghettos? To do away with faith-based education entirely would be to do away with some of the best and most over-subscribed schools in the country. Would that be a price worth paying for a more cohesive society, or a monstrous display of religious intolerance? The morality of faith schools.