Image copyright Getty Images Image caption There have been debates about whether face veils should be allowed for teachers and pupils

Ofsted chief Sir Michael Wilshaw has told inspectors in England they can fail schools for allowing face veils.

Sir Michael says inspectors can rate schools inadequate if wearing Islamic face veils are a "barrier to learning".

Education Secretary Nicky Morgan has said such decisions about veils were up to the uniform policies of individual schools.

Sir Michael says he wants to give his "full backing" to heads wanting to impose a ban on face veils.

The Department for Education says it is "clearly right" that if veils are interfering with learning that Ofsted should take action.

The Muslim Council of Britain says Ofsted did not need to resort to the "megaphone of the media to show that it is flexing its muscles".

Head teachers' leaders say that inspectors should not be judging schools on dress codes.

The Ofsted chief said he was concerned that some heads were "coming under pressure" to relax a ban on face veils, either for staff or pupils.

Image copyright PA Image caption Sir Michael says inspectors could fail schools if wearing veils limits teaching

"I want to assure these leaders that they can rely on my full backing for the stance they are taking," said Sir Michael.

He said that inspectors could downgrade schools, or rate them "inadequate", if they thought wearing a veil was damaging teaching.

"I have also made clear to my inspectors that where leaders are condoning the wearing of the face veil by staff members or by pupils, when this is clearly hindering communication and effective teaching, they should give consideration to judging the school as inadequate."

The Ofsted chief says he has written to all inspectors with this advice and says schools can be "marked down" if wearing the veil stands in the way of "positive social interaction".

Sir Michael said that discrimination "on the grounds of gender, has no place in our classrooms".

The Muslim Council of Britain called for "accommodation" over wearing the veil.

"It is a shame that the niqab - the full face veil that a minority of Muslim women wear - has become a polarising issue when it need not be."

Leora Cruddas of ASCL head teachers' union said Ofsted should not be judging schools on uniform policies. "Inspectors should focus on what schools achieve rather than what people wear."

Andrew Clapham, an academic in Nottingham Trent University's education department, said: "Ofsted's threat to penalise institutions where the Muslim veil is worn has no basis in research."

"There is no credible evidence base to suggest that wearing a piece of clothing on one's head has an impact on intellectual or academic ability."

Kevin Courtney of the National Union of Teachers criticised Ofsted for threatening schools. "Rather than assisting school leaders this will have the effect of alienating many staff and pupils."

A Department for Education spokesman said "we fully support" the statement from Sir Michael that head teachers who "restrict the wearing of the veil to support effective teaching and learning will receive Ofsted's backing".

"It is also clearly right that if the wearing of the veil is interfering with education in schools that should trigger action from Ofsted."