Labour has championed the integration of special needs pupils in mainstream education and 93 special schools have closed in England since 1997.
The proportion of pupils educated in special schools has remained the same, though legislation in 2001 strengthened their right to be educated in a mainstream school.
But a TES survey last month revealed that teachers believe as many as 25,000 children are in mainstream education who would be better off in special schools.
The Conservatives have been campaigning to save special schools. Baroness Warnock, the architect of inclusion, has also now said that many pupils with disabilities would sink in mainstream education.
Getting the balance right between integration and protecting potentially vulnerable pupils is tricky and the variety of solutions being employed suggests there is no obvious answer.
ITALY opted for a big-bang approach in 1977, closing special schools almost overnight as new laws provided for integrating special needs pupils into mainstream classes.
The policy did not get off to a good start. Most schools and teachers were not ready for the change. But things have improved and the increasing number of children with statements who stay in education after the school-leaving age of 15 suggests integration is working.
By 2003 there were 143,000 statemented children in state schools - more than 2 per cent of the population - taught by 74,000 special needs teachers working alongside classroom teachers. A generation of Italians has now grown up with the belief that it is not necessary to send special needs children to separate schools.
Most other developed countries have a mix of special and mainstream schools but with variations in emphasis.
Japan has a 130-year-old history of education for special needs children and until a recent policy change the majority were educated in special schools. Some, with less severe needs, attend mainstream schools where there are support systems, though not on a full time basis.
They receive extra support through one-to-one group lessons for several hours a week in resource rooms set up inside special schools.
In Sweden, a special needs school system runs parallel to the mainstream system but the policy is to include children in the mainstream where possible. Parents can decide whether their child attends a special school if the local authority offers them a place. Places are offered to children who cannot follow the national curriculum.
In Spain the majority of the country's 100,000 special needs pupils are educated in mainstream schools. Specialist support staff (teachers and psychologists) regularly assess pupils to find out what they need and provide extra lessons. Some groups, particularly maths and language classes, are split so special needs children can be taught separately. But there are regional variations.
America has been committed to integration since 1975 and 96 per cent of the 6.8 million "individuals with disabilities" attend mainstream schools. Half are in mainstream classes for at least 80 per cent of the time where many will get individual instruction, often from a dedicated assistant. They also attend small special education classes with a trained teacher. The 2001 No Child Left Behind Act made no exception for special needs. Schools were accountable for their academic progress and faced escalating sanctions for missing targets. Earlier this year officials agreed to exempt students with "the most significant cognitive disabilities".
Germany and Australia operate mixed systems. Australia's eight education departments have different policies. Pupils with severe disabilities go to special schools. But there is pressure to integrate as many pupils as possible, to be assisted by special assistants at least some of the time.
In Germany, children with learning, speech or behavioural difficulties are integrated as far as possible. Children with severe disabilities attend special schools. Nationally-agreed criteria identify and diagnose needs by assessing and testing learning capacity and behaviour, as well as intellectual, social and motor development and general state of mind and health.
France runs separate classes in mainstream schools. Disabilities are assessed at the equivalent of county level by a commission which decides on appropriate care. It is government policy wherever possible to integrate children with disabilities into local mainstream schools. In September this entitlement became law, ensuring the introduction of extra staff to give individual support to the increasing numbers of special needs pupils who are attending mainstream schools, and better organisation of the integration networks.
Additional reporting by Jane Marshall, Alex Leith, John Walshe, David Newbold, Jon Buscall, Stephen Phillips, Michael Fitzpatrick, Geoff Maslen