The Chief Rabbi has been accused of a U-turn after endorsing plans for an Orthodox school which could offer up to 50 per cent of places to non-Jewish children.

Parents in Golders Green have applied to the government to open a free primary school there. The school has the backing of Lord Sacks and will be presided over by Golders Green United Synagogue's Rabbi Harvey Belovski.

The school, which will have a modern Orthodox ethos, will be required to accept 50 per cent of pupils on a faith basis and 50 per cent on proximity.

The backing for the school comes almost two years after the United Synagogue fought and lost a case in the Supreme Court to prevent a child, whose mother's conversion was not recognised by the Chief Rabbi, from having a place at JFS.

Orthodox rabbis have also previously condemned JCoSS, the new Jewish school which offers places to children whose families consider themselves Jewish, regardless of affiliation. Rabbi Belovski described it as having a "confused ideology that conflicts squarely with basic Orthodox principles".

Rabbi Ariel Abel, the director of Jewish Identity Projects, a programme aimed at strengthening Jewish identity, and former rabbi of Radlett United Synagogue, said: "Following the JFS case and JCoSS episode that preceded it, I question the surprising U-turn in policy by centrist Orthodox leadership on the matter of the mixed schools proposed.

"On what is it halachically based? How can it forecast that the mixed schools model will not lead to inter-marriage and assimilation, any less than cross-communal education?

"Whereas a primary school in Golders Green may comfortably fill its intake with Jewish pupils, other areas will not.

"I therefore question not only the basis of the rabbinic endorsement given now, but also question how those rabbis imagine they will cope with the religious consequences of their endorsement.

But the Chief Rabbi said: "The government's free school programme has opened up the possibility of the provision of Jewish day schools where, without the significant benefits of the free school regulations, Jewish children would otherwise be deprived of a Jewish education. In such cases I fully support the initiatives being undertaken.