Sir Michael Wilshaw, the head of Ofsted, is generally an admirably plain-spoken man, willing to talk with refreshing candour about problems in the education system that others refuse to confront. Yet his letter revealing his inspectors’ findings about scores of unregistered schools operating in England is curiously circumspect, almost mealy-mouthed. Referring to the risk that children face “indoctrination”, Sir Michael does not explain exactly which harmful ideas could be foisted on those children.

Nor would Ofsted confirm publicly that many of these unlisted schools are operated by British Muslims, parents who do not want their children to be taught in the state school system. This refusal to state plain facts is deeply troubling. If even senior officials responsible for overseeing the education system and identifying its problems are unwilling to say openly that the evidence suggests that some British Muslims are rejecting British values, how can the country ever attempt to address that problem?