A legal battle over the right of Jewish schools to define who is a Jew is to be heard by the Court of Appeal.

The case is being brought on behalf of a boy known as “M”, who was turned down by the JFS Comprehensive in Kenton, north London in September 2007 because his mother is a Progressive convert.

After a four-day hearing in March last year, Mr Justice Munby upheld the United Synagogue school’s right to reject applicants who do not meet the Orthodox definition of Jewish status.

He ruled that its entry policy did not breach race relations law.

Now lawyers are to mount a fresh challenge in May, in a case which pits individual human rights against the freedom of religious institutions.

If they succeed, it could force Jewish schools to rewrite their admissions policies.

A spokesman for the United Synagogue, which was a party to the original action, said: “We won in the court of first instance and regret that we have now been taken to appeal — at even more cost to the community. However, it is an important case and we have to defend it.”

The government has supported JFS, arguing that the decision of who was, and who was not, a Jew was a matter for the school’s religious authority, and not for the courts.

The Reform movement, although critical of JFS’s entry policy, also backed the United Synagogue’s position.

In an official statement at the time of the original action, its head, Rabbi Tony Bayfield, said that it was “an internal matter for the Jewish community. We would not want the law of the land to question the right of the Office of the Chief Rabbi to define Jewish identity the way that it does.”

However, Liberal Judaism has taken a different line. Its chief executive, Rabbi Danny Rich, said this week: “The way JFS has applied its admissions criteria is unfair, politically motivated and highly inappropriate for a state-aided school. JFS should not be a private club for certain approved sections of the Jewish community.”