Heads of independent schools have been warned by the Department for Education that they could be in breach of educational standards if inspectors are unable to speak to pupils.

While the DfE has not said what specifically prompted the letter, Ofsted reports reveal inspectors at some Charedi schools over the past year have been denied permission to speak to pupils by parents, or had access restricted.

In the letter, the DfE said inspectors needed to gather “first-hand” evidence about teaching, the curriculum and safeguarding issues.

“However, we have become aware that some schools have taken steps to try and prevent this from happening - either by a lack of co-operation during the inspection and/or actively hindering inspectors, or through encouraging parents to provide written confirmation that they do not wish their child to be allowed to speak to inspectors.”

It warned that schools could be in breach of standards designed to “ensure that information reasonably requested by inspectors is provided in connection with an inspection”.

In a recent inspection of a Charedi school in Manchester, Yeshivah Ohr Torah, inspectors reported they were prevented from speaking to pupils about personal development, safeguarding issues or anti-bullying policies because “parents had withdrawn consent.”

Ofsted said that when it inspected one of Stamford Hill’s largest schools, Beis Rochel d’Satmar, it had received more than 900 letters from parents “with the request that inspectors did not to speak to pupils or ask them any questions”.

On the second day of the inspection, inspectors did receive permission to talk to pupils in class.

At another Stamford Hill School, Beis Chinuch Lebonos, inspectors were able to speak to “small groups” of pupils, but on condition they did not ask questions about personal and social education or “science teaching, such as reproduction, sexting and different lifestyles”.

Inspectors were also asked not to discuss whether the school promoted respect for all of the protected characteristics mentioned in equality law - which include same-sex orientation and gender re-assignment.

New draft guidelines on independent school inspection recently published by Ofsted emphasise the need for inspectors to talk to pupils about safeguarding, bullying and British values. If not, Ofsted says,“it is unlikely that the school will be able to provide inspectors with the evidence they need to be able to conclude that these aspects of the school’s provision meet the requirements of the independent school standards”.