Many more children are hidden from the authorities in unregistered schools across England than previously thought, Ofsted’s chief inspector has said.
Sir Michael Wilshaw said a crackdown had found more than 100 suspected illegal schools. The majority were Islamic or Jewish, Oftsed said.
Seven warning notices have been issued to schools in London, Wolverhampton, Birmingham, Luton, and Stoke-on-Trent.
Any school offering 20 hours of lessons a week must be registered.
Unregistered schools are those that operate outside the supervision of the Department for Education, local authorities or Ofsted inspections.
They are often run by faith groups, and there are concerns about the safety of pupils in their charge. It is understood most of the schools were Islamic or Jewish.
In a letter to Education Secretary Nicky Morgan, Sir Michael said his team of seven experienced inspectors, working closely with DfE officials, had identified more than 100 suspected unregistered schools across the country.
“The evidence they have gathered so far during so far during this short period firmly reinforces my belief that there are many more children hidden away from the view of the authorities in unregistered schools across the country than previously thought,” he said.
During the inspectors visits, which took place last month, 350 children had been found on the premises of these schools, Sir Michael said.
He said such schools provided a sub-standard education, placed children at risk and undermined the government’s effort to ensure all schools promote British values.
He pledged swift and decisive action against those who are operating illegal schools, and thereby putting children at risk of harm.
This included the risk of exposure to extremism and radicalisation, he said.
And the inspectors were “deeply alarmed ” by what they had found.
Sir Michael said health-and-safety risks had included: serious fire hazards such as obstructed exits, unsafe and unhygienic premises, staff and volunteers who had not been properly checked or cleared to work with children. Also found was that these schools were using the freedoms of parents to home educate their children as a cover for their activities.
“They are exploiting weaknesses in the current legislation to operate on the cusp of the law,” he said.
“Many are charging parents thousands of pounds to send their children to these unregistered schools.”
Shadow Education Secretary Lucy Powell accused the government of being “asleep at the wheel” and allowing extremely worrying and potentially dangerous practices to evolve in the schools system.
“The Tories’ education policy has led to a fragmented schools system lacking robust local oversight to spot and tackle serious problems early on.
“As a result, many children are dropping off the radar or ending up in illegal, unregistered schools for months or years, where they are at risk of being exposed to harm, exploitation, or the influence of extremist ideologies.”