One of the first National Challenge schools to be inspected since the scheme's launch in June has been found to offer "an outstanding standard of education and care for its students".
Ofsted inspectors' report on Canterbury High, in Kent, noted: "The outstanding achievement of students results from a combination of good teaching, an excellent, innovative curriculum and outstanding care, guidance and support."
Canterbury High was among the 638 English secondaries singled out by the Government because fewer than 30 per cent of GCSE pupils achieved five A*-C grades, including in maths and English. The schools are under the ultimate threat of closure if results fail to improve.
Last year, 90 per cent of Canterbury High pupils achieved five good grades at GCSE, but only 30 per cent included English and maths.
Phil Karnavas, headteacher of the secondary modern school, points out that Canterbury has three grammar schools, as well as selective Church of England and Roman Catholic comprehensives. "Selection takes 32 per cent of 11-year-olds out of the system and sends them to grammar schools," he said. "You can't take children out of the system because they're good at maths and English and then batter the other schools for the consequences of this."
Many Canterbury High pupils come from disadvantaged backgrounds: significant numbers are eligible for free school meals, and have special needs. But the school ranked 10th in the country last year for its contextual value-added score.
"I'd like to see a recalculation of the way National Challenge schools are identified, so that it includes attainment and achievement," said Mr Karnavas. "The two are not the same. Schools with low attainment and high achievement should be supported. The question is: is a school doing as well as it should be, given the nature of its intake?"
John Bangs, head of education for the National Union of Teachers, said: "An outstanding Ofsted report ought to be cause for major celebration. But the National Challenge has translated enormous success into failure. This is utterly damaging to the self-confidence of schools in tough areas."
A Government spokesman said: "We have always said that many National Challenge schools are doing good work, often in challenging circumstances."