But behind closed doors there are concerns about 118 “socially conservative” independent faith schools - the vast majority of them Muslim - where pupils may be encouraged to cut themselves off from mainstream society.

Ministers have been told they do not have “detailed information” about the religious orientation of the groups and movements behind all independent faith schools.

And officials have privately admitted that they also have no system in place to identify institutional extremism in state schools, the Daily Telegraph has learned.

They say there is also “a gap between what we think we know and what we can prove” because they cannot use undercover methods open to journalists.

From January, the Independent School Standards will require a respect for “fundamental British values” including democracy, the rule of law, individual liberty and mutual respect and tolerance of those with different faiths and beliefs.