The latest liberal assault on the concept of any sort of national identity or sense of group self-belonging has come with an Appeal Court ruling which has forbidden a London Jewish school the ability to define who is a Jew and who is not.

The ruling – which may have implications for not only faith schools but all groups and organisations which have an ethnically based character, including the British National Party – was made after Lord Justices Sedley and Rimer, and Lady Justice Smith said it was “clear that Jews constituted a racial group defined principally by ethnic origin and additionally by conversion.”

The case was brought before the Appeals Court after the state-funded Jewish school JFS refused to admit a pupil whose father was Jewish by birth but his mother not.

The Appeals Court judges ruled that ethnic tests of Jewishness amount to racial discrimination. Faith schools may discriminate on religious grounds but the Court held that this involved a test of ethnicity – which they said is unlawful.

The JFS, formerly the Jews’ Free School, gives preference to applicants whose Jewish status is confirmed by the United Synagogue, which in turn requires that the mother of the child be Jewish, in accordance with Jewish law.

The case in question involved a child, named M, whose mother converted to Judaism from Catholicism in a Progressive synagogue not recognised by the Orthodox United Synagogue.

The father of the child appealed against the decision to exclude his child, and the Appeals Court has now ruled in his favour.

 ”The refusal of JFS to admit M was accordingly, in our judgment, less favourable treatment of him on racial grounds.

“This does not mean … that no Jewish faith school can ever give preference to Jewish children. It means that, as one would expect, eligibility must depend on faith, however defined, and not on ethnicity.”

The United Synagogue said the decision affected any branch of Judaism that defines who is a Jew on the basis of descent (whether matrilineal or patrilineal).

It said Jewish schools of any sort – Reform, Liberal, Masorti, Charedi, Orthodox, Federation and so on – would be prohibited from giving priority to applicants who were a member of the Jewish faith.

It added: “In future, all Jewish schools (whether state or independent) will need to adopt a religious practice test, until such time as the Court of Appeals’ ruling is successfully overturned or a legislative amendment is made.”

“Unless the Court of Appeals decision is overturned on appeal it will have a very serious effect on all Jewish schools and on many of our communal organisations.”

While the full legal ramifications of the ruling will have to be carefully considered, there can be no doubt that it is a serious blow to any organisation or group which seeks to self-define its membership criteria. This could have important implications for a party such as the BNP, which also self-defines its membership.

Although there is a large difference between a state-funded faith school and a privately financed political party, all BNP members should be aware that the latest ruling represents a serious threat to any group which seeks to preserve its identity.