At the time, special needs pupils were often labelled "educationally sub-normal" and taught separately in special schools or units.
Mary Warnock, now a baroness, started a revolution by suggesting one in five children had special needs at some time. She said they should, where possible be in the mainstream. "Statements" of their needs would ensure they got the right support.
A quarter of a century later, Labour took this policy to its logical conclusion with the special educational needs and Disability Act 2001 which gave parents the legal right to place children in a mainstream school unless it would harm the education of other children. But the political tide seems to be turning. The system has faced criticism from Ofsted and the Audit Commission, the public spending watchdog.
And last year, Baroness Warnock partially reversed her earlier position and criticised "blind faith" in inclusion.
Under pressure from the Conservatives, teaching unions concerned about rising bad behaviour and some campaigners, the Government has emphasised it still sees a role for special schools. Nevertheless, the number of special schools has fallen by 117 since 1997 to 1,122 .
This week's report will increase pressure on the Government to find extra resources or reverse its inclusion policy. Both the Conservatives and the Government have launched their own reviews of policy. And the Commons select committee will announce the results of its own inquiry next month.
But supporters of inclusion insist it produces better results. Richard Rieser, director of Disability Equality in Education and a National Union of Teachers activist, said: "I am not at all sure Lord Adonis, the schools minister, wants to see more inclusion as it might get in the way of his academies project. I would urge him to stand firm. Disabled pupils in mainstream schools do on average seven times better in GCSEs than their peers in special schools."