Up to 6,000 children are being educated in illegal schools across England putting their safety and education at risk, a watchdog has warned.

Figures published by Ofsted have revealed that unregistered schools that have no formal external oversight of safeguarding, quality of education or health and safety are a ‘huge’ nationwide problem .

The data shows a quarter of these schools are in London, with ‘alternative provision’ being the most common type of setting. A fifth of the settings are religious instruction, while a quarter are general education providers.

Ofsted have issued 71 of those settings with a warning notice, resulting in 15 closing and 39 changing the way they operate to comply with the law.

Ofsted’s deputy director, Victor Shafiee, said: ‘These settings deny children a proper education and can leave them at risk of harm.

‘The problem here is first and foremost about safeguarding. 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.’

Ofsted is calling for extra powers to allow inspectors to collect evidence they find in unregistered schools.