Nine-year-old Lewis Sismey is one of thousands of vulnerable children secretly and unlawfully excluded from school every year.

Lewis, who suffers from Down Syndrome, which has left him with impaired hearing, is routinely sent home in a taxi by his school at lunchtime and barred from swimming and physical education because the school claims that it cannot cope with his needs.

Tracey Sismey, his mother, said Lewis had completed no more than two full weeks at Clackclose primary since October.

The school in Downham Market, Norfolk, had failed to meet the terms of his statement and employ a teaching assistant with British sign language, she said.

As a result, Mrs Sismey is regularly asked to keep Lewis at home because the school has no one to look after him.

Lewis has also been formally excluded from school for 45 days because of bad behaviour, something Mrs Sismey said has been exacerbated by a lack of support from the school.

Nationally, about a third of the exclusion cases dealt with by the Independent Panel for Special Education Advice (Ipsea), a parent support group, are of the unofficial variety. Ipsea has estimated that up to 20,000 children in England suffer back-door exclusions each year, but John Wright, its spokesman, said it was difficult to get an accurate idea of the scale of the problem.

Because informal exclusions are not recorded, schools continue to receive funding for the pupil, but children are not provided with an alternative education. “Often the local authority does not know the exclusion has happened and parents and children are left in limbo,” Mr Wright said.

Earlier this month, a Norfolk council report said special needs children have been sent home early or asked to stay away because schools say they cannot cope.

Conservative-controlled Norfolk is among the first authorities to pledge to tackle “back-door” exclusions, which special needs groups say are a national problem. John Gretton, Conservative spokesman on Norfolk’s scrutiny committee, described the situation as shameful.

Lewis’s parents have applied for a judicial review of the way the school and the education authority have treated their son.

They are now considering whether to accept a place at a special school.

John Ward, head of Clackclose primary, said he could not comment for legal reasons.

A Norfolk county spokeswoman said: “We have Lewis’s best interests at heart and have been working hard to try and find a solution that will meet his needs.”

* jon.slater@tes.co.uk