An independent school serving one of Stamford Hill’s main Chasidic sects has more than doubled in size in under five years in contravention of  its official registration conditions, Ofsted reported on Tuesday.

Inspectors have so far refused to give their blessing to the Vishnitz Girls Scholl in Hackney to expand partly because pupils lack sufficient understanding of those with other faiths and lifestyles.

But although the school is registered for 124 pupils from the ages of three to eight, its roll now stands at 261 and including girls up to the age of 12.

“The school has more than doubled in size, admitting pupils in years five, six and seven without the permission of the Department for Education,” Ofsted said. “This is in breach of the school’s registration agreement.”

In summer 2013, when it was ranked good by inspectors, the school had only 103 girls on its books.

But after a serious of critical reports, it has now been downgraded to inadequate, despite the teaching of secular studies and educational outcomes for pupils being considered good.

Ofsted commented: “While pupils understand the importance of tolerance and respect for others in principle, they do not have any real understanding of other faiths or the full range of differences found in modern Britain. This, together with pupils’ limited contributions to the wider community and understanding of how to safe online, means that they not prepared well enough for life in modern Britain.”

Although they learned about democracy through visits to the Houses of Parliament for example, there were “very few opportunities to broaden pupils’ minds through mixing or contributing to society beyond their school or faith communities”.

Pupils lacked sufficient understanding of people with “different characteristics”. Guidelines for independent schools refer to groups protected under equality law such as those of same-sex orientation or transgender status.

Pupils worked hard, were polite and courteous and reached a good development on leaving reception class, Ofsted said.

But the school lacked an “overarching policy” for its curriculum and schemes for PE and art lacked depth.