The kind of bad behaviour normally seen in rowdy teenagers at secondary school is increasingly being exhibited by primary pupils, an education expert has warned.
As a result, primary heads are having to expel and suspend children at an ever earlier age to retain order, said Professor Jim Campbell, an expert in primary education at Warwick University.
He blamed poor parenting and aggressive role models portrayed through the media and advertising for the trend.
His warning comes in the wake of Government figures showing that nationally nearly 45,000 pupils under the age of 11 were suspended in 2004/05.
More than 1,000 primary pupils were permanently excluded during the period - 60 of them under the age of five.
In Birmingham, 1,231 pupils were suspended from 300 primary schools during the 2004/05 academic year. A further 43 were permanently expelled.
Prof Campbell said: "The kind of bad behaviour that was not unusual for secondary school pupils has shifted down the system, particularly in some inner city schools.
"Before, people were not terribly surprised if secondary school pupils behaved in a way that would lead to exclusion.
"But it used to be slightly shocking if a primary school pupil behaved in a way that warrants exclusion. It's not now."
Prof Campbell blamed a "loss of innocence" in the young. "Fundamentally what we have lost is a conception of childhood. We have media and advertising focused on young people because parents spend money on them.
"The kind of focus they are providing for young people to identify with includes behaviour that translates to b ad behaviour in the classroom.
"For example, walking around swearing and shouting at people. Images of masculinity and femininity are largely aggressive and self-centred. This kind of behaviour goes around unchecked on the streets and in shopping centres, so why wouldn't that be transferred to the classroom?"
Government policy has responded by encouraging teachers to adopt a "zero tolerance" to misbehaviour and disruption in class.
Prof Campbell said that inevitably led to an increase in exclusions.
"I don't blame schools or teachers because without it their job becomes almost impossible.
"The responsibility lies with us all but particularly with the parent. I have seen parents fighting in the playground while waiting for their children.
"What kind of a model is that?
"There have always been groups of parents who have not been able to look after their children and act as good role models.
"But there is a lot more family break-up now and it is more difficult to discipline, particularly boys."
Figures from the Department for Education and Skills show boys are much more likely to be suspended than girls. More than 42,000 boys were suspended in 2004/05 from primary schools, compared with just 4,220 girls.
However, Prof Campbell predicted a breakdown in society would see bad behaviour among girls also increase.
"My guess is ten years down the line there will be a lot more girls suspended or excluded from primaries because that is what is happening at secondary level," he said.
Some schools, however, were successfully tackling the "moral fracturing of society" by providing an "oasis of peace, calm and order".
"There are some schools that are tremendously strong, almost like churches were in the past," said Prof Campbell. "They are havens of peace and order with clear moral structures where the world outside offers very little of that."