Special schools have emerged as the unsung heroes of value-added tables, outperforming their mainstream peers at GCSE and in key stage 3 tests.
In the tests for 14-year-olds, nearly 30 special schools outscored Skegness grammar, England's top mainstream performer in the league tables published for the first time last month.
And at GCSE, the results were almost as striking: 14 special schools did better than the top-placed mainstream school, Sir John Cass foundation school in Stepney, east London.
The value-added results have been welcomed by headteachers as recognition of their work tailoring learning to pupils' varying special needs. However, the findings should be treated with some caution, as many of the top-performing non-mainstream schools had fewer than 10 pupils taking tests.
Mainstream schools took the media spotlight when KS3 results were published on December 19 and the GCSE scores were announced last week.
But now an analysis of special schools' performance at KS3 reveals that 29 outscored the top mainstream secondary, Skegness grammar school in Lincolnshire.
Schools are given a value-added points score, which reflects the progress made by pupils. The measure for KS3 compares the achievements of pupils with identical test scores at KS2.
The school listed by newspapers as top performer for progress between KS2 and 3 Skegness grammar, scored 104.2 on this measure, where every point above 100 equates to a term's more progress than average.
However, Woodeaton Manor school, near Oxford, scored 108.7. The school had only eight pupils taking KS3 tests and has been earmarked for closure because of falling rolls.
Laleham, a beacon school in Margate, Kent, catering for children with severe dyslexia and other communications difficulties, was the highest placed state school among those testing 30 or more pupils. Its score was 106.7 At GCSE, pupils' performances are compared against results at KS3.
The Royal National Institute for the Blind's New College in Worcester, a selective non-maintained boarding school for visually- impaired pupils, scored 131.7 on this measure, compared to 113.5 at Sir John Cass, the top mainstream school.
The 131.7 score is staggering - it suggests that pupils scored 31.7 GCSE points, or the equivalent of five B grades, more than the national average among other youngsters with the same achievement at KS3.
And Laleham school scored a rare double, outperforming all mainstream state schools at GCSE as well as KS3, with a score of 115.
Chris Darlington, president of the National Association for Special Educational Needs, said any comparison based on the figures should be made cautiously, because special schools were different from mainstream schools.
However, Mr Darlington said: "These results show that, even though special schools are expensive to run, they are actually providing very good value for money, despite educating what are often fairly challenging groups of young people."