Education Secretary Nicky Morgan has called for a review of home schooling amid concerns that thousands of children are being radicalised by their own parents.

It is unclear how many children and young adults are being home schooled but it is thought to be in the region of 20,000 to 50,000.

Parents do not have to inform their council that they are educating their children at home, leaving the government in the dark about the number of kids at risk of radicalisation through education at home.

Education Secretary Nicky Morgan has called for a review of home schooling amid concerns that thousands of children are being radicalised by their own parents

'There has always been the freedom in this country for people to educate their children at home. Many people do it very well,' a senior government source told the Independent on Sunday.

'But we need to know where the children are and to be certain that they are safe.

'For every parent doing a brilliant job, there may be someone filling their child's mind with poison. We just don't know. We don't have reliable figures,' the source said.

The Education Secretary's new approach comes after the announcement of an investigation into the activities of unregistered schools and madrassahs.

Concerns have been made about the teaching in some madrassahs with concerns that religious extremists are using an inappropriate curriculum.

Ofsted’s chief schools inspector, Sir Michael Wilshaw has previously spoken about the 'serious and growing threat' of unregistered Islamic centers

The Education Secretary's new approach comes after the announcement of an investigation into the activities of unregistered school and madrassahs

Ofsted’s chief schools inspector, Sir Michael Wilshaw has previously spoken about the 'serious and growing threat' of unregistered Islamic centers.

'We have provided Ofsted with extra inspectors to eradicate extremism in education,' a Department of Education spokesman said.

'We are working with them to address their concerns about home education being exploited, while safeguarding the rights of parents to determine how and where to educate their children.' they said.

Labour’s shadow Education Secretary, Lucy Powell has called for urgent action against the threat of extremist content being used in home school curriculums, calling the failure of action 'completely unacceptable.'

'It is vital that action is taken to ensure that all children, whether in school or taught at home, are given the knowledge and skills to succeed, not taught a narrow curriculum of hate and bigotry.'

'Yet, just last week it was revealed that the Government had let children remain in illegal, unregistered schools for weeks, where they were exposed to narrow curriculums, misogynist, homophobic and anti-Semitic material. This is completely unacceptable.'