LONDON, April 12 (Xinhua) -- Thousands of children in England are being taught in illegal schools, a report by the official school's standards inspectorate Ofsted revealed Friday.
New data, revealing the scale of the problem, said suspected illegal schools, a quarter of them in London, are a huge nationwide problem.
It showed Ofsted has investigated 521 of the so-called schools and inspected 259 since January 2016.
Ofsted estimates that as many as 6,000 children are being educated in the unregistered schools it has so far inspected.
"These children are potentially at risk because there is no formal external oversight of safeguarding, health and safety or the quality of education provided," said Ofsted.
About 23 percent of the settings investigated are in London, with the rest spread fairly evenly across the country.
An unregistered school is defined as a setting that is operating as an independent school, without registration. It is a criminal offence in England to operate such schools.
Ofsted's Deputy Director Victor Shafiee, said: "We continue to have serious concerns about unregistered schools. As today's data shows, this is not simply an issue with faith settings, nor is it limited to certain areas of the country. Unregistered schools come in many shapes and sizes, and not all of them are run with malicious intent. But, all children deserve the best. These settings deny children a proper education and can leave them at risk of harm."
Shafiee added: "Many of these places are unsafe, with poor facilities and hygiene, badly trained or untrained staff, who may not have had any employment checks made on them, and little care for children's health and well-being."
There is currently no legal definition in England of "full-time education", but schools must operate from a building, and offer a curriculum that includes maths and English.
Ofsted's unregistered school taskforce was established in 2016 to investigate and inspect suspected illegal schools. The team receives one million pounds of annual funding from the government's Department for Education. (1 British pound = 1.31 U.S. dollars)
