Ofsted has asked the government to look closely at Steiner schools in England, after multiple inspections of schools operating under the Steiner banner revealed worries over pupil safety.

The letter from the head of Ofsted throws into doubt the future of Steiner schools receiving state funding, after several opened as part of the free schools programme launched by Michael Gove in 2011.

Amanda Spielman, the chief inspector of schools in England, said in a letter to the education secretary, Damian Hinds, that the government should “carry out a thorough examination of the underlying principles of Steiner education and consider the extent to which they may have contributed to the common failures we found in our inspections.”

Spielman also urged the Department for Education (DfE) to close down inadequate Steiner schools that failed to show rapid improvement.

“Overall, the findings are deeply concerning. They demonstrate that there are a number of areas of common weakness in these schools, which mean that in many cases, the children attending them are inadequately safeguarded and are receiving a poor quality of education,” Spielman said.

Ofsted inspectors had witnessed “inappropriate physical handling” of pupils by staff and cases of governors ignoring parents’ complaints about teacher behaviour, she said.

Six out of nine state and private Steiner schools recently given full inspections by Ofsted were rated as inadequate, the lowest grade, while the three others were given the next lowest grade: requires improvement.

Three of the state-funded Steiner schools – the Steiner academies in Bristol, Exeter and Frome – have been placed in special measures.

A fourth state-funded Steiner academy, in Hereford, received a “good” judgment in December. Recent DfE data showed the Hereford pupils to be making rapid progress, while GCSE grades were good but less impressive.

Steiner schools subscribe to a pedagogy developed by Rudolph Steiner, an Austrian writer with eccentric views on child development. It translates into allowing pupils to learn at their own pace, in many cases not being taught to read or write until years after children in conventional schools in the UK.

The Steiner Waldorf Schools Fellowship, which represents Steiner schools and nurseries in the UK, said: “It is a matter of deep regret when individual schools fail in their duties. There is no compromise where the welfare of pupils is concerned. Our role is to provide guidance to schools in order for them to ensure all standards are in-line with the requirements set out by the DfE.

“Whilst we celebrate the good outcome for Steiner Academy Hereford, we are disappointed that six schools have been judged as inadequate, and have taken immediate action to ensure that standards rapidly improve as per Ms Spielman’s recommendations.”

In reply to Spielman’s letter, Hinds said DfE and Ofsted officials should review the evidence from the schools’ inspection reports to discover “what may be lying behind those schools that are failing to meet the standards”.

Hinds said the three inadequate academies would be taken over by other multi-academy trusts, while enforcement action would be taken against the independent schools if they did not improve quickly.

Spielman’s letter also said the Steiner schools had a poor approach to educating children with special educational needs and disabilities (Send). “At one of the schools found to be inadequate in all areas, inspectors reported that some staff and senior leaders blamed pupils with Send for all the problems in the school,” she said.