Ofsted’s chief inspector has warned against those using religion to “actively pervert” education.

In a speech today Amanda Spielman is expected to speak in defence of the headteacher of a primary school, which banned the youngest Muslim girls from wearing the hijab.

Ms Spielman will also tell the audience at the Church of England schools conference that school leaders should adopt a “muscular liberalism” to defend their decisions and not to be scared about causing offence.

According to reports, she will say: “Ofsted inspectors are increasingly brought into contact with those who want to actively pervert the purpose of education.

“Under the pretext of religious belief, they use education institutions, legal and illegal, to narrow young people’s horizons, to isolate and segregate, and in the worst cases to indoctrinate impressionable minds with extremist ideology.”

She is also expected to tell schools they have a responsibility to “tackle those who actively undermine fundamental British values or equalities law”.

“Uncomfortable decisions” need to be made in the interests of pupils and not in the interest of the most conservative sections of a religious community.

“Similarly schools must not allow pressure from certain elements of school communities to dictate school policy, nor should we allow vocal parental minorities to pressure other parents and children to act or dress against their wishes. Giving way to the loudest voices is the opposite of tolerance,” she will say.

In November Jewish educational organisations voiced concern over Ofsted’s intention to ask Muslim girls in primary schools why they were wearing hijabs.

Rabbi David Meyer, executive director of Partnerships for Jewish Schools, described the move as “very troubling”.

The Board of Deputies said it would seek clarification from the education authorities on how Ofsted proposed to carry out its inquiries.

Many Strictly Orthodox schools have been criticised by Ofsted over their teaching of "British values".