This week a High Court judge rejected the claim that separating girls and boys for lessons in a state-aided faith school amounted to discrimination.

But his ruling still seems to leave the door open to a case being brought under the 2010 Equality Act against certain Orthodox schools.

Mr Justice Jay backed the right of an unnamed Islamic state school to segregate boys and girls from nine to 16. The school had challenged the view of the inspection service Ofsted that dividing the sexes in a mixed school fell foul of equality law.

Nevertheless the judgment was not so simple. The judge said separation could be considered discriminatory if it led to girls receiving an inferior education to boys. In the case of this Muslim school, however, Ofsted had found no evidence it had.

The judge noted that one Jewish state school which operates on two campuses had been rated outstanding by Ofsted. (He must have been referring to the Hasmonean High School in London.)

He rejected the argument that segregation in itself reflects an archaic worldview of women as inferior.

But here is how some Jewish schools might be vulnerable to legal challenge. Specifically, state-aided Jewish schools which offer different Jewish studies programmes to boys and girls.

It would be unlawful to offer boys and girls different science courses, for example, in a mixed school. But it has been assumed religious studies were exempt from the legislation and schools were free to organise them according to their religious beliefs.

Ofsted's guidelines state that where segregation exists on religious grounds, " there must be good educational reasons for doing so."

Suppose you have a Jewish school where girls and boys are separated for Jewish studies and the boys learn Talmud and the girls do not. It could be argued boys are receiving a more advanced Jewish education than girls. So now could we see a Jewish school in court?