Amanda Spielman, the chief inspector of Ofsted, also wants stronger powers to tackle unregistered faith schools

Children are leaving school without being taught to read or write in English, it emerged yesterday, as the head of Ofsted said a resistance to British values in some communities was affecting education standards.

Amanda Spielman, the chief inspector, said some schools were deliberately illegal and unregistered, operating off the radar so that they did not have to meet education requirements.

Launching her annual report, she said children at many illegal faith schools left education with limited or no ability to read and write in English, no qualifications and no work skills.

Ofsted wants greater powers to tackle them, including a new legal definition of “school” and the ability to seize inflammatory material.

“Imparting British values can sometimes go against community wishes or norms and