In a draft report on the impact of the inclusion framework, Ofsted says that support for children varies widely. In only three out of ten schools studied was additional help given to pupils when were a year behind in their reading. Most others waited until they lagged three years behind chronological age.

Shirley Cramer, chief executive of the Dyslexia Institute, thinks parents would be outraged to know their children had to fall so far behind before they could expect any help. “It is a wait and fail model,” she says.

Around 4 per cent of children have moderate to severe dyslexia, but research suggests as many as one in ten are affected. Awareness and understanding are improving, as are screening and assessment programmes, but campaigners say they still battle against negative images: dyslexics are seen as lazy or trying to buck the system by getting extra help in exams.

Diagnosis has improved with the arrival of computer programs - such as nferNelson’s new dyslexia screener - which replace written tests with “games” designed to assess reading, writing and phonic ability and measure intelligence through verbal and non-verbal reasoning tests. The mismatch between general intellectual ability and literacy reveals the presence of dyslexia.

Standardised scores in such programs allow teachers with no specialist training to identify dyslexic pupils. The Dyslexia Institute says it has had positive results from trials where every child is screened. But this remains rare.

Ideally, children would then be referred to an educational psychologist for a full assessment - as happens at Brighton College - and help in drawing up a support plan. But here the pattern is even patchier, and the issue even more heated.

Brian Harrison-Jennings, general secretary of the Association of Educational Psychologists, says seven out of ten authorities have vacancies they cannot fill. With so many statutory duties, assessing dyslexia is a low priority. Attempts at early intervention - by training teachers to identify cases - becomes impossible.

Only the more severe cases get a statement; and even then, Ofsted says, there is no guarantee it will be followed.

Mr Harrison-Jennings says the literacy strategy has helped bring a more consistent approach to teaching, which has enabled earlier diagnosis. But the BDA believes other policy changes have been less positive. More SEN funding is now devolved to schools and the Government has attempted to reduce the number of children with statements.

Combined with inclusion and an emphasis on different learning styles, that means that some children are falling through the net, says Carol Youngs, the association’s policy director. “Some schools don’t want to label children, saying they all learn differently. Parents are put off with platitudes.”