Pupils as young as four are among the growing number of those permanently excluded. A large proportion of the 14,000 pupils who found themselves excluded last year were primary-age children or young black men.
While exclusions for pupils of all ages have risen by 450 per cent in the past five years, the fastest increase has been in primary schools - 30 per cent in the past year alone.
The situation is now so bad that next month schools minister Estelle Morris is to be presented with plans for an "early warning system" to avert problems before it is too late.
Tim Linehan, of the Children's Society, said: "The numbers are spiralling out of control. We cannot take children this young out of education without seriously damaging their futures."
The Children's Society has piloted a new scheme, SHINE (Schools Have Inclusive Education), which offers children at risk of exclusion one-to-one support in school.
Six-year-old Dathan Fraser-Matthews was temporarily excluded from Trinity St Mary's primary school in Balham, south-west London, after a playground fight. Dathan's mother, Denise, said: "I'm an active parent and had already been having weekly meetings with Dathan's teacher to try and sort his problems out. The exclusion itself was a terrible shock and had a big impact on our family. "
Dathan's teacher referred him to SHINE and for 12 weeks he had a weekly "temper management session". Ms Fraser thinks this has helped Dathan: "In his own words he's glad he doesn't get into trouble any more and is a much happier, less resentful child in class."
Ms Fraser believes black boys "are noticed more, get harsher treatment and are less likely to be given another chance".
African-Caribbean boys are four to six times more likely than their white counterparts to be excluded, often rendering them unemployable, dependent on benefits and at risk of offending.
This week the Commission for Racial Equality with the Prince's Trust issued new guidelines "Exclusion from School and Racial Equality: A Good Practice Guide" to schools nationwide. They aim to encourage schools to reduce exclusions through measures including: greater involvement of pupils and parents when drawing up behaviour policies; training for all those involved in the exclusion process; and more emphasis on racial equality and equal opportunities in the curriculum.
Commission chairman Herman Ouseley said: "A significant proportion of black young people are being denied the right to adequate education. The power of exclusion should be an absolute last resort. The long-term costs of exclusions are considerable."
Next month the Local Government Association is to meet Estelle Morris to present proposals for an "early warning" system, whereby any pupil facing exclusion must be the subject of a case conference involving the head, LEA and parents to try to find alternative solutions.
Graham Lane, LGA education chair, backs the CRE proposals. He said: "The number of black exclusions is frightening and there are very few people doing anything about it. Often the first time the local authority learns of an exclusion is after it's been endorsed by governors, who endorse almost automatically.
"The problem is worse in grant-maintained schools, where pupils are often persuaded to transfer instead of being excluded. It's tantamount to the same thing. The pressure to attract the best pupils and be top of the league tables means children who don't contribute to good results are the most at risk, " he said.
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