A headteacher has criticised Government’s “politically-motivated tinkering” with exams and generalised judgments from education inspectors after his school was judged to be inadequate in its latest Ofsted report.

Trevor Lawn, head of Alec Hunter Humanities College in Braintree, claimed Ofsted made “assumptions on the basis of results, rather than on what they actually see.”

Inspectors who visited the school over two days in October said teaching quality and pupil achievement were inadequate.