Tim Rogers's Staffordshire school plummeted from the top 1 per cent in a national league table to the bottom 6 per cent in a single year following erratic key stage 3 English results.
The head of English at Newcastle community high was pleased when in 2002 71 per cent of his pupils achieved level 5 or above in the tests - a result that made the school as one of the best in the country in the KS2 to 3 value-added league table.
But Mr Rogers was dismayed when the same teaching team using the same methods managed to get just 39 per cent of pupils to the same level the following year. The figure increased to 49 per cent after 25 pupils had their papers re-graded on appeal but the school still dropped to the 94th percentile in the value-added table.
This year 72 per cent of pupils reached level 5 and the school is in the top 25 per cent in the value-added table.
Mr Rogers is in no doubt the see-sawing is caused by problems in the key stage 3 test marking. He believes the marking scheme is too complex and too subjective for examiners, especially those who are inexperienced.
This was not helped, he said, by the complexity of some of the questions, such as the one in the Shakespeare paper exploring the nature of trust in Macbeth. Questions which are difficult to answer will be difficult to mark, he said.
Mr Rogers said that at a feedback conference last year senior markers for the exam board AQA admitted even they found much of that year's papers difficult to mark.
"If it's difficult for a senior examiner to mark, how are kids supposed to answer it?
"If senior markers haven't got the confidence in the test where do English teachers stand? It affects your confidence in any of them being right. We feel as if we are teaching on shifting sands."
Mo Laycock, head of Firth Park, Sheffield, believes this year's test discriminated against ethnic minority and working-class pupils. The story in the writing paper featuring diamonds stolen from a stately home was "very middle England", she said.
Mrs Laycock said changes to the tests' format, with the answer papers being split into two parts, also confused many of her pupils.
She said: "A lot of what we do is about familiarity with the paper, ensuring that kids feel confident and believe in their ability to succeed.
If the way the paper is presented is changed you have to be a particularly confident sort of person to get your head round that and our kids just panicked."
Mrs Laycock sent all her papers back to the AQA exam board to be re-marked and is still awaiting the final results.