John Platten has a framed letter from Jim Knight, schools minister, displayed in his headteacher's office.
It congratulates him on the contextual value-added score that Alderman Peel High, in Wells-next-the-Sea, Norfolk, achieved in last year's GCSEs results.
Its score of 1033.6, produced after taking pupils' backgrounds and previous achievements into account, makes it one of the highest performing schools in the country.
That is an important accolade for a secondary which will never top the league tables for raw scores because it has one of the most socially deprived intakes in Norfolk.
"What we haven't really got in this area is a middle class," said Mr Platten. "We have some very wealthy people, often in second homes, and a surprisingly high proportion of social housing."
This helps to explain why less than a quarter of pupils have gained five A* to C grade GCSEs including English and maths for three years running. That statistic not only makes Alderman Peel High one of the Government's National Challenge schools, but puts it among the 240 ministers suggested are most at risk of closure and replacement with academies or trust schools.
Mr Platten says the school is working hard to improve in English and maths. But he is angry that by putting it under such public pressure last week, ministers appear to have ignored his pupils' background and Ofsted's 2006 description of the school as "good with outstanding features".
"This appears to be entirely politically motivated," he said. "It is demoralising, demotivating and illogical."
Brian McClarin, head of King Richard School, serving the deprived Paulsgrove estate in Portsmouth, also received a letter from Mr Knight in January, congratulating the school on its excellent value-added GCSE performance.
He was "baffled" to find he was also one of the 240 National Challenge schools under most pressure.
"This is a kick in the face to me, my staff, my pupils and their parents," he said. "It is a sop to the Daily Mail.
"I know there are staff in the DCSF as exasperated about this as me. But my parents don't know that."
The Government has emphasised that the pound;400 million National Challenge is about giving schools the support they need to get more than 30 per cent of their pupils to pass the GCSE benchmark, and that structural changes will only be made when absolutely necessary. Ministers have also avoided using the word "failing" to describe the schools, although Gordon Brown used the word "failure" when he announced the scheme last year.
Opposition fierce on Balls' home ground
Ed Balls faces potential embarrassment over plans to place nine schools in his West Yorkshire constituency under a single trust, removing them from direct local authority control.
Mr Balls, the Secretary of State for Children, Schools and Families, sees trust schools as a key solution for National Challenge schools.
But the scheme has met with fierce local opposition and campaigners say the plans to give the status to all but one state school in the town of Ossett is a partial privatisation that will commercialise education.
They are particularly concerned that Jacobs, an engineering company proposed as one of the trust partners, is helping to run the Aldermaston Atomic Weapons Establishment.
"We are worried about the message this partnership might send out," said Sally Kincaid, National Union of Teachers secretary at Wakefield.
But the schools proposing the trust said their relationship with the local authority and other schools will not be affected. They say it means greater opportunities for pupils. - William Stewart.