A leading Jewish state school broke race laws by refusing to admit a boy whose mother had converted to the religion, the Court of Appeal ruled yesterday.

JFS, formerly the Jewish Free School, is highly oversubscribed and has turned away several pupils for not meeting its criteria of Jewishness. Previous court hearings have supported its stance. Yesterday, however, the court ruled in favour of the parents of a boy named only as M.

The school, in Brent, northwest London, rejected the 12-year-old child because his mother converted to Judaism at a Progressive rather than Orthodox synagogue. M’s father is Jewish, but custom dictates that the faith line passes through the mother.

The judges said that “the requirement that if a pupil is to qualify for admission his mother must be Jewish, whether by descent or by conversion, is a test of ethnicity which contravenes the Race Relations Act”.

The ruling will have widespread implications for other faith schools and puts the court on a collision course with the Office of the Chief Rabbi, Sir Jonathan Sacks, from which the school takes its definition of which children are Jewish.

It strikes at the heart of whether being Jewish is a religious or racial question and means that such schools will now have to adopt a religious practice test.

JFS said that it was “disappointed” and would seek leave to appeal to the House of Lords — a decision supported by Sir Jonathan. “I have advised the leadership of JFS that they have my full personal support,” he said.

Other Jewish groups, however, welcomed the ruling, saying they had been marginalised and discouraged from speaking out. Rabbi Danny Rich, the chief executive of Liberal Judaism, said: “The JFS, a state comprehensive funded by taxpayers, has been exclusively following one Jewish religious authority and ignoring the rest. We object to standard-setting by just one section of the community to the detriment of the rest. The JFS will now be open to children from all types of Jewish background.”

The court ruling stated: “It appears to us clear that Jews constitute a racial group defined principally by ethnic origin and additionally by conversion and that to discriminate against a person on the ground that he either is or is not Jewish is therefore to discriminate against him on racial grounds.

“If for theological reasons a fully subscribed Christian faith school refused to admit a child on the ground that, albeit practising Christians, the child’s family were of Jewish origin, it is hard to see what answer there could be to a claim for race discrimination. The refusal of JFS to admit M was accordingly, in our judgment, less favourable treatment of him on racial grounds.”

John Halford, who represented the boy’s father, said: “It is unlawful for a child’s ethnic origins to be used as the criterion for school entry. Such a practice is even more unacceptable in the case of a comprehensive school funded by the taxpayer.”

Many other Jewish schools operate according to similar policies and will be affected by the court’s decision.

David Lightman’s daughter was also turned away by JFS because it did not accept her Jewish status, even though her mother is head of English at the school. Mr Lightman, an Orthodox Jew, said yesterday: “This is a victory for common sense and religious freedom. We are talking about two Jewish children who want an education. If the school thinks it’s worth spending millions of pounds to stop that happening, then they need to re-examine what Judaism is about.”

JFS is one of Britain’s oldest Jewish schools and is the largest Orthodox Jewish school in Europe, with 2,000 pupils. It is described by Ofsted as outstanding and is oversubscribed every academic year.

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