Lib Dems have hit out at government claims that "feckless" parents are to blame for increased violence in the classroom and on the nation's streets.

Disruptive and unruly schoolchildren have also been blamed for the sharp rise in the number of mobile phone thefts and in a speech to the Association of Teachers and Lecturers on Wednesday, the education secretary Estelle Morris is set to say that poor parenting is causing a "cycle of disrespect".

Phil Willis, education spokesman for the Liberal Democrats, believes blaming the parents is "typical" of government scapegoating for its own education failures.

"Blaming a minority of parents for the government's failure to meet the needs and aspirations of our poorest communities is typical of this administration. The vast majority of our schools are seeing unprecedented levels of support from parents. The government must stop creating scapegoats for the failure of its own policies," he said.

"Pupils with challenging behaviour need specialist provision, which is largely unavailable, and an education system that offers them real aspirations and real hope."

As the spring teaching union conferences begin, Morris is set to make an opening speech focusing on the problem of classroom disruption.

"How can we expect pupils to respect teachers when their parents don't. Parents must set the right example, and most do. But there is a hardcore of feckless parents who have a corrosive effect on the rest. There is a cycle of disrespect starting in school and lasting throughout these children's lives," she will say.

Her comments follow Tony Blair's speech last Friday in which he said that behaviour inside and outside the classroom by the nation's children was now the number one government priority. Morris will repeat his demand for councils to make wider use of parenting orders, which were introduced by the government in 2000, whereby violent parents can be ordered to attend counselling or face court and a fine.

And on Monday the prime minister attended an anger management class for unruly pupils, where he told miscreants that: "Silence is often the best weapon".

Blair's tip came as he was asked how he handled personal insults at a pupil referral unit in Tower Hamlets. Five pupils excluded from local schools in the borough were learning how to cope with school situations responses to situations when they felt teachers and other pupils were insulting them. The centre's head teacher, Tony Crisp, turned to the PM and said: ``You must have received insults before?''.