Dr Mary Bousted, general secretary of the Association of Teachers and Lecturers, told the Daily Mail: "What our teachers are telling us is that there is definitely a rise in bad behaviour of little children who seem to have very short fuses and who suddenly just kick off .
"When a child at primary level is out of control, that quickly leads to physical aggression, because they don't have the vocabulary to express themselves. It leads to lashing out and that is the overwhelming reason children in primary schools are being excluded."
She said the root of the problem is the failure of parents to impose consistent boundaries at home.
Many of today's mothers and fathers seem to want to be their children's friends, rather than their parents, she told the newspaper.
"There is a rise in the number of parents afraid to impose boundaries because their child will say, 'You are a bad mummy,' or 'I don't like you'," said Dr Bousted.
"School is often a child's first experience of being in a public place, where different rules apply. It's not the child's fault they've not experienced those boundaries."
Last month, it was reported that 90 primary school children in Britain are sent home every school day for attacking teachers or classmates.
The number of primary school children suspended for physical assaults on other children was 9,160 in the 2010/11 academic year.
Another 7,830 children were suspended for assaulting adults.
The newspaper interviewed several teachers and most agreed that the blame for this explosion of violence can be laid squarely at the feet of parents.
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