While the government's primary concern is to prevent religious extremism that could lead to violent radicalism, Sir Michael has made clear that inspectors are ready to be tough with other unregistered schools teaching pupils under 16.
The Department for Education admitted earlier this year that it had a list of more than 20 unapproved yeshivot teaching boys in Stamford Hill, north London. But its wish to register them has been legally challenged.
In response to a Freedom of Information request from the JC, an official said a number of yeshivot had argued that "they are not required to register as independent schools because their wholly religious curriculum suggests that they are not providing secondary education". Therefore, they fell outside the definition of "school" according to the 1966 Education Act.
Only the courts, the official added, could decide "whether or not a particular institution is, in fact, a school" and the department was still considering the issue.
The government has proposed new legislation which would enable Ofsted to inspect supplementary schools such as cheders and Islamic madrassas and could bring yeshivot into its net. Their educational content would have to be shown not to "undermine" British
values.
Within the Charedi community, differences remain over whether yeshivot should be registered amid concerns over issues including the teaching of same-sex relationships.
The JC Podcast: Education special