The largest Charedi school in the UK has been told it is in breach of equality law because it teaches boys and girls separately.

Beis Rochel d’Satmar Girls School in Stamford Hill, which has 1,712 pupils, takes boys up to the age of 12 but teaches them in a different building.

A year ago the Appeal Court ruled it was illegal for a state-aided Muslim school entirely to segregate boys and girls - although single-sex schools remain acceptable.

Beis Rochel leaders told Ofsted they plan to split it into separate boys' and girls' schools from next month.

The school, ranked overall as requiring improvement, was already above its official maximum of 1,475 pupils, inspectors noted.

They said boys made less progress than girls and literacy skills remained weak in the early years.

But the introduction of English to the Yiddish-speaking pupils in the early years had had a “positive impact,” whereas before English was taught only from year two.

Girls performed particularly well in maths and art in GCSE, while English and maths passes were above the national average.

Although the school had a sixth form, around one in five girls left to get married before achieving any qualifications.

Inspectors found that textbooks had been edited; in one, the sight of bare arms in images had been redacted, in another a reference to the Ice Age.

But the school met the requirements for teaching British values. “Leaders promote respect for the full range of protected characteristics, in line with the school’s equality and diversity policy,” inspectors commented.

“For example, leaders emphasise respect and tolerance in the way they respond to pupils questions about different types of family group.”

Over the past few years, strictly Orthodox schools have consistently run into problems with Ofsted’s requirements to take account of the full range of “protected characteristics” in equality law - which include same-sex orientation and gender reassignment.

Another strictly Orthodox independent school, also recently ranked as requiring improvement, Yesodey Hatorah in Stamford Hill, was criticised for not ensuring that pupils had been made aware of “all the protected characteristics”.

The school -  which teaches primary-age boys and girls, and boys at secondary level - was also reported to be in breach of equality law for segregating the sexes. However, Ofsted said “secure plans” were in place to register the girls’ building  as a separate school.

The level of teaching in both religious and subjects at Yesodey Hatorah was good.

In another recent report, an independent Charedi boys school, Talmud Torah Chinuch Norim in Salford, which has applied to raise its age limit from 12 to 13, has been told by Ofsted it was now meeting the necessary standards.

Meanwhile, Chinuch UK, the representative group for Charedi education launched earlier this year, is encouraging supporters to sign a general petition expressing concern over plans for relationships and sex education.

The government has suggested that the RSE teaching should include same-sex relationships.

The petition voices “grave concerns about the physical, psychological and spiritual implications of teaching children about certain sexual and relational concepts proposed in RSE and believe that they have no place within a mandatory school curriculum”.