Pupils with special needs and disabilities are at risk of being "segregated and ostracised" by the coalition Government's policy of watering down inclusion, according to campaigners.
Dr Artemi Sakellariadis, director of the Centre for Studies on Inclusive Education, has written to the newly formed Department for Education to express her concern about the policy.
"The only people who think inclusion is a bad idea are those who have not seen it working properly because of lack of resources," she said.
Pupils at Bromstone Primary in Broadstairs, Kent, have a wide range of needs. Headteacher Nigel Utton said he and his staff had worked hard to make the school inclusive.
"Putting children in special schools is divisive and against social cohesion; I thought David Cameron wanted to create an inclusive society," Mr Utton said.
Simone Aspis, campaigns and policy co-ordinator for the Alliance for Inclusive Education, said: "It's an absolute disgrace that a coalition that talks about promoting fairness and equality wants to remove disabled children's rights to access mainstream schooling.
"This policy will turn the clocks back by 30 years, where disabled children will grow up living segregated lives."
Around 158 local authority-run special schools closed between 1998 and 2007, with the number of pupils educated in them falling by 9,000.
Lorraine Petersen, chief executive of Nasen, which supports pupils with special needs, said she did not think Mr Cameron wanted to stop all children with special needs from receiving a mainstream education.