We cannot afford to let intellectual snobbery leave us with a second-class, second-best vocational education system.”

So said Ruth Kelly, the Education Secretary, a year ago, as she unveiled plans, in a white paper on 14-19 education, to “place the same emphasis on vocational education as we currently have on academic”.

Today The TES publishes new research revealing how far the Government has to go in realising its dream of equal status for academic and work-related learning.

One in five comprehensives reserves vocational courses for pupils with special educational needs, the Qualifications and Curriculum Authority has discovered.

Courses defined as vocational in this context include national vocational qualifications, which are work-related, and general national vocational qualifications, a hybrid of academic and work-orientated study.

The QCA’s findings are not unprecedented. Last November, after a survey of 140 secondaries, Ofsted said some schools did not see the relevance of work-related learning for high-achievers.

Schools have recently been given more scope to increase work-related learning. Since 2004, 14 to 16-year-olds have been allowed to drop subjects such as languages and design and technology to enable them to focus on vocational courses.

Why is the QCA’s finding so shocking? It seems uncontroversial that SEN pupils, many of whom may struggle with an academic curriculum, might be motivated by more practical courses.

But the damning part of this statistic is the revelation that some schools are only offering these courses to these pupils. Those who might fare well on either an academic or a vocational route - some of the academic high-achievers -are given no choice by their schools but to go for GCSEs and A-levels.

These schools do not believe vocational courses have value for any pupil who could do well on an academic route. If this is the case, how can vocational provision command credibility among those assigned to it?

Concern about this seems near universal. John Wright, legal support worker for the Independent Panel for Special Educational Advice, a SEN charity, said: “This is worrying. It makes a nonsense of the Government’s pro-inclusion approach if, once they are in mainstream schools, SEN pupils are being herded together on particular courses. It suggests schools are perhaps just finding an easy way of coping with children with SEN, rather than providing them with full access to the curriculum.”

Ian Carnell, of the Science, Engineering, Manufacturing Technologies Alliance (SEMTA), which represents 100,000 employers from aerospace to nanotechnology, was also concerned. He said: “Employers want the brightest young people they can possibly get hold of. It is not doing the young person, or the employer, any favours if provision is just seen as being for low-achievers.”

Sir Mike Tomlinson, who led a review of secondary exams, said it was “fairly common” for schools to use vocational provision to keep lower attainers occupied, rather than to stretch them.

But are schools to blame for taking this approach? Or are they right to steer as many pupils as possible away from courses which are not valued by employers?

Alison Wolf, professor of public-sector management at King’s college, London, who has been a persistent critic of vocational provision in British schools, said that GNVQs, in particular, were not prized. She said: “A 14-year-old who is capable of passing GCSEs well, should be passing GCSEs well, (rather than taking vocational exams), because otherwise they are cutting off their opportunities.”

This view is disputed by some schools. Jean Hickman, head of Walsall academy, said GNVQs were valued by employers, and that pupils of all abilities at her school took them.

Much vocational provision for 14 to 16-year-olds is offered through the Increased Flexibility Programme, which allows pupils to spend part of their school week in colleges.

The programme, launched in 2002, now caters for 100,000 young people, and is widely seen as a success. Ofsted said last year that many schools were committed to a curriculum that meets all pupils’ needs.

But in the worst, it was only offered to pupils who were losing interest in school. A separate report, by Sussex Learning and Skills Council, found many students felt they had been “dumped” in colleges because their schools did not want them.

The TES has reported in recent years how many schools are putting large numbers of pupils on GNVQs. Often, however, this has been a move to improve their league table positions, while some secondaries have targeted the qualifications at lower achievers.

David Blunkett, former education secretary, told The TES that the education Bill, which says all pupils must be given access to a range of vocational diplomas from 2008, was a sign that things may be about to change.

The diplomas are being introduced following Sir Mike’s inquiry, which said that the hundreds of work-related courses on offer to learners were confusing to employers and contributed to their low status.

Ms Kelly was widely criticised for rejecting Sir Mike’s recommendation that all pupils would take diplomas, rather than just those pursuing vocational options. Many teachers said this would preserve the academicvocational divide.

The QCA’s and Ofsted’s findings reveal that unless the diplomas are perceived to be very different from the courses they will replace, they will not have credibility in many schools.