When exam league tables were first published in 1992, Canterbury High School was named as one of the worst-performing secondaries in England. Just 5 per cent of its pupils achieved five good GCSEs.
But, since then, the school has taken big strides forward. Now more than 70 per cent of its pupils get five A to C grades at GCSE, with 27 per cent of pupils doing so with English and maths. On contextual value-added scores last year, it was the 10th best in the country.
Keith Hargrave, its former headteacher, was awarded a CBE this year for his work.
But despite its achievements, Canterbury High is one of the 638 schools on the Government's hit list.
Phil Karnavas, the current head, said he was outraged by ministers' "simplistic and superficial" branding of his school as weak.
"Despite everything we have done, we are back at square one," he said. "This week's announcement outrages me on behalf of the children. In the pursuit of soundbites, the Government fails to take into account the impact on children when you castigate their schools."
Mr Karnavas said the situation was made worse because Kent operates a selective system.
Grammar schools in his area "cream off" the pupils who are best at English and maths, he said. And he also believes there is confusion between achieving a C-grade in English and maths and being functionally literate and numerate.
"No child leaves this school functionally incapable," said Mr Karnavas, who believes that his school will pass the 30 per cent benchmark this year.
"Clearly the Government is right to challenge under-performance, and clearly everyone in education wants to do the best they can for their children," he added.
"But schools that are struggling need constructive support, rather than being battered, threatened and bullied."