Playground patrols have already been trialled in London

Home Office sources said the change would allow the authorities to "nip offending behaviour in the bud" before it develops into full-blown criminal activity.

It will mean the families of delinquent teenagers will be required to attend parenting classes, often before their child has even been arrested or appeared in court.

The proposal - and the much-speculated police playground patrols - is expected to be announced by Mr Blunkett at a youth crime conference on Tuesday, at which Metropolitan Police Commissioner Sir John Stevens will speak.

According to the Independent on Sunday, a special group of 44 officers in 10 London boroughs will be created to patrol schools that have been identified as breeding grounds for street crime.

Bullying

The Metropolitan Police would not confirm exact details of what Sir John will announce at the conference, organised jointly with the Home Office and Youth Justice Board.

But a spokesman said: "They are looking at building closer relations between schools and police to tackle anti-social behaviour, bullying and violence.

"A number of initiatives will be looked at for preventing youth crime."

The National Assocation of Schoolmasters Union of Women Teachers has welcomed police in schools, saying it would be a welcome step towards reducing attacks on staff.

We must stop youngsters making a mockery of the police

Home Office source

There has already been a pilot scheme in the London Borough of Southwark, with the police setting up a regular presence in secondary schools across the borough.

A comprehensive school in Essex has also experimented with hiring security guards to prevent disruptive behaviour.

A senior Home Office source said extending parenting orders would mean mothers and fathers taking more responsibility.

He added: "We must stop youngsters making a mockery of the police. That means all agencies, including government, police and local councils, taking a tough stance.

"But it also means parents must take greater responsibility for out-of-control kids.

Parenting orders, which can last up to 12 months, can include 10 counselling and guidance sessions giving advice on controlling children and enforcing sensible discipline.

They can also include requirements for the child to attend school regularly, keep away from certain people or locations and remain at home at night-time.