Pupils with statements of special educational needs make up only about 2 per cent of all pupils. The number in mainstream schools has more than doubled in only eight years and, as a deliberate policy, is now about twice as many as are in special schools.

The most dramatic growth has been in special needs pupils without statements - a category introduced in 1994. Such pupils now make up more than 16 per cent of school rolls in secondary schools and more than 19 per cent in primary schools.

What does it cost? The total expenditure on SEN pupils could be as high as pound;7.1 billion out of a national education budget of about pound;20 billion - more than a third of the total. But nobody - not even David Blunkett - really knows.

What else don’t we know? We don’t know - and nobody knows - where the money goes or what it is spent on. We don’t know - and nobody knows - what criteria are used to put pupils on special needs registers because each school and LEA does it differently. We don’t know - and nobody knows - how many pupils there are at each of the four levels set out in the Government’s Code of Practice or how many boys and how many girls have special educational needs. We don’t know - and nobody knows - what types of specific handicap or need constitute special needs or how many pupils there are with each specific type. We don’t know - and nobody knows - how many pupils with special needs cannot read or whether they are being, or ever have been, taught to read.

And we don’t know whether or not al the funding actually improves pupils’ learning or increases their knowledge.

This list of unanswered questions is far too long. Money is going in increasingly large amounts into a black hole of unknown size.

The much-delayed SEN and Disability Rights in Education Bill is likely to make the system more complex, bureaucratic and expensive without putting right any of the major problems outlined above.

What should be done? The Code of Practice should be withdrawn because it is so imprecise as to be virtually meaningless.

All special needs pupils should take external tests of reading and spelling each year. If they show no progress, the funding should be stopped.

Reading should be taught earlier and we should introduce the Continental practice of pupils repeating a year of schooling if they fail to reach the required standard.

The Government’s policy of inclusion should be abandoned. The case for special schools is much stronger now than it was in the early 1980s especially since the development of the national curriculum. Many parents actually prefer them to mainstream schools and many teachers favour inclusion in theory more than in practice.

For pupils with the worst problems, we should revive the concept of defining specific categories of handicap as we used to do in this country and is still done in many other countries.

A national inquiry should establish the scale of the present waste of resources and monitor the effects of the proposed changes. It is a public disgrace that so little has been done to shed light on such an important and expensive matter.

John Marks

What are Special Educational Needs? An analysis of a new growth industry, by John Marks, pound;7.50 from the Centre for Policy Studies, 57 Tufton Street, London SW1 3QL. Tel: 0207 222 4488