Some children are simply too naughty to fit into everyday school life, the Government's behaviour tsar suggested today.
There is a group of youngsters who behave in very difficult and violent ways and who need much more help and support, according to Charlie Taylor.
He suggested that there may be have been a rise in these types of pupils, many of whom display very bad behaviour from an early age.
Giving evidence to the Commons education select committee this morning, Mr Taylor - former headteacher of The Willows, a special school in west London for children with behavioural, emotional and social difficulties - said that while behaviour in general is improving, there remains a groups of children that persistently behave poorly.
He was asked by Neil Carmichael, Conservative MP for Stroud, why it was that increasing numbers of pupils are suspended from school for abuse or assault and, at the same time, Ofsted rates almost four-fifths of schools as good for behaviour.
Mr Taylor replied that the numbers of schools rated as good has fallen from around 87% as the bar has been raised on standards of behaviour.
He told the committee: "Though I would say generally, the trajectory of behaviour within schools is improving"
It is now rarer in schools to have "no-go areas where teachers fear to tread at lunchtimes and break times", Mr Taylor said.
"So things have improved.
"But I do think there's a group of children who show very extreme behaviour, very difficult, challenging, violent behaviour, often quite young children, and I would say possibly there has been an increase in those sorts of children.
"You can still be a school who is good on behaviour and still have pupils like that within your school because you're doing a good job with them.
"But nevertheless there are certainly a group of children who need extra interventions, who need more help, who need more support and for whom the basic standards of just a really well-run school aren't enough."
He added: "The trajectory is in the right direction, but there's a huge amount to carry on doing."
Mr Taylor has just been appointed the first chief executive of the Teaching Agency, which will oversee teacher training.