Schools in Waltham Forest have introduced knife checks

Almost half of secondary schools in England have a dedicated police officer, suggests a survey.

Children's Secretary Ed Balls and Home Secretary Jacqui Smith have repeated calls for all schools to join such partnerships with the police.

There are over 5,000 schools in Safer School Partnerships with the police, including 20% of primary schools.

These schemes can "prevent problems with youth crime before they escalate", says Mr Balls.

The idea of putting police into schools - either as a full-time presence or as regulator visitors - is intended to tackle bad behaviour, cut truancy and build a relationship between youngsters and the police.

Anti-social behaviour

It was launched in 2002, originally with plans to base 100 extra police officers in schools in 10 specific areas.

According to the Department for Children, Schools and Families and Home Office, this has now grown to include 45% of secondary schools across England - with some cities having police in every school.

Earlier this year, it was announced that every secondary school in Leeds would have a police officer, provided by a team of 24 officers.

Police involvement has become an increasingly visible part of school discipline.

Figures published last year showed that police were called to violent incidents in schools more than 7,000 times.

Waltham Forest in east London is believed to be the first local authority in England to introduce weapon checks at all its secondary schools.

Mr Balls, launching new guidance for Safer School Partnerships with Ms Smith, says there have also been benefits from police officers providing a positive role model for young people.

"This will help them develop into young adults who care about the communities they live in," said Mr Balls.

The home secretary said that "prevention is vital in stopping young people from getting involved in bad behaviour in the first place".

"Safer School Partnerships reduce the risks of young people turning to crime and anti-social behaviour."

There has also been support for these partnerships from the police.

"Through these partnerships we are also better able tackle the causes of violent extremism and to deal with specific issues that are of concern to young people such as bullying, weapons, drugs, alcohol and gang culture," says Metropolitan Police deputy assistant commissioner Rod Jarman.