It’s a bit puzzling. That’s the first thing to say about the Al-Hijrah case. Actually more than a bit puzzling.

The decision by the Appeal Court that an Islamic school should not be allowed to educate boys and girls separately leaves an obvious question hanging. What about Eton? Or, come to that, North London Collegiate? Or any number of single sex state schools.

The ruling seems to suggest that while you can educate boys and girls separately on two campuses, you cannot do so on a single campus. This will not prevent segregation, it will just force schools who practise it to move to two sites. Could it, for instance, affect Hasmonean’s plans to move to adjacent buildings?

And even if the ruling were to be extended to all single-sex schooling, it isn’t obvious that it would produce greater equality. Many academics argue that girls are the main winners when there is separation between the genders.

The ruling is worrying in another way. There is a delicate balance to be struck between allowing faiths to maintain their own traditions and ensuring everyone who lives in this country is educated to be part of mainstream British life.

I worry that this case reflects the difficulty that Ofsted, the school inspectorate, and now the courts have in getting to grips with this admittedly difficult problem. If this had been an Anglican school that happened to be separated into single-sex establishments on the same campus, I very much doubt it would ever have ended in court.

So this ruling is a symbol of unease with faith schools. And while I strongly agree that nothing should be allowed in a faith school that would be illegal anywhere else, I also think that nothing should be illegal in a faith school that would be legal anywhere else.

That all having been said, I don’t think it’s a mystery how they came to make what looks to me, on the surface of it, rather like a blunder.

The first thing is this. The school’s case is that education of the sexes is separate but equal. I haven’t been there so all I can go on is their contention. But if the girls’ school taught more about being “homemakers” than the boys’ school did then it would certainly not be the first faith establishment to do so. I think, if we are honest about it, that our own faith schools are not as careful as they might be in conditioning boys and girls to regard themselves as equal.

Traditional roles in the home can be reinforced in religious institutions. So maybe Ofsted was concerned about this.

The second point is that complete segregation between girls and boys is not very good preparation for modern life. Some separation between the sexes in schools can play a role, and even be good for girls, as I’ve noted. But cutting boys off completely from girls is not healthy or right.

Recently I have been campaigning, successfully as it turns out, for a statue of the women’s suffrage leader Dame Millicent Fawcett to be placed in Parliament Square. One of my objectives is that, placed in this location, her monument should be a symbol that equality for women is part of the modern British identity (albeit that it is still an objective rather than a reality).

While accepting that different communities have different backgrounds and traditions, I believe we have a right to insist upon certain common standards of citizenship, and equality for women is such a standard. I have long believed this is something the Jewish community should reflect upon. We are, I’m afraid, still a very long way from ensuring such equality.

Insofar as Ofsted is trying to question and challenge the idea of complete segregation, I understand entirely why they find it troubling. And I share a suspicion that separate will not mean equal, a claim that was made in the American Deep South, when they tried to justify Jim Crow.

So I see what they are trying to do. But this particular decision does seem heavy-handed and, as I’ve said, a bit puzzling.

Daniel Finkelstein is associate editor of The Times