With reference to unqualified teachers being employed by academies, this sort of thing has been the case for some time in further education. Perhaps through poor organisation, perhaps for financial reasons, classes are taught by staff unqualified to teach; qualified to teach but in a different subject; lacking experience; or teaching at a higher level than is comfortable. I know of one college at which GCSE maths was taught by an unqualified "trainer demonstrator" (a sort of officeclassroom assistant) while experienced staff were underused elsewhere. In another, there was a long delay in advertising for a replacement maths teacher, despite the previous incumbent giving plenty of notice of their resignation. This led to another maths teacher being made to teach for some weeks out of her depth to A level.
Michael Byrne, Canterbury, Kent.