Boys as young as six are being recruited into gangs, according to a police strategy document obtained by The Times.

Efforts to tackle gang membership among secondary school pupils are doomed to fail, say the authors, because by that age vulnerable children are already immersed in the culture.

The document, which calls for a new approach to confronting the gang menace, has been produced by the South Yorkshire Police, which is fighting a growing threat from so-called postcode gangs in Sheffield.

Other British cities have identified a trend towards primary school pupils becoming involved in gangs, often as couriers for drugs and guns. Police in Sheffield are the first to say publicly, however, that six-year-olds are vulnerable to exploitation by gangs.

The South Yorkshire Police document states: “A key age for young people is six, and we have seen many examples of young people getting recruited into gangs at this age.

“A key age in terms of offending is about 12, and this effectively means we need to move the focus of interventions from secondary to primary schools.”

Sources said six, seven and eight-year-olds were being sucked into the gang culture because they looked up to older siblings and acquaintances who had made money and earned “respect” from selling drugs and carrying weapons.

Recruitment was taking place in schools, youth clubs, playgrounds and on street corners. The youngest children had been used as messengers and lookouts by teenage drug dealers. Police in Sheffield are drawing on the experiences of other cities, especially Manchester, which have also devised programmes for diverting children away from the gangs.

Boris Johnson, the Mayor of London, is unveiling today his youth crime action plan, which will encourage children to join movements such as the Scouts, Girl Guides and Police Cadets.

Three young men have been murdered in gang fighting in Sheffield since October last year - Jonathan Matondo, 16, Brett Blake, 23, and Tarek Chaiboub, 17. Another youth was wounded in a shooting at the weekend.

On Friday night police raids on properties linked to gang members resulted in the seizure of a significant number of handguns and ammunition.

The search operation came after the acquittal on Friday of Negus Nelson, 19, an alleged member of the city's S4 gang, for the murder of Matondo, a member of the S3 gang who was shot dead last year.

The trial at Sheffield Crown Court lifted the lid on the extent of the gang culture in the city.

The court was told of dozens of shootings and stabbings involving rival gang members in the two years before the killing. Very few had led to prosecutions.

Detective Inspector Matthew Fenwick, of South Yorkshire Police, said that the few witnesses who came forward invariably asked for anonymity because they were afraid of reprisals.

“People are not just afraid of the offenders, but also of other gang members and the extreme measures they may take to prevent somebody co-operating with the police,” Mr Fenwick said.

“By operating in this way the gangs discourage people from assisting police not just in relation to these crimes but crimes in general,” he added.

Gang feuds have erupted over minor incidents and led to gun and knife attacks. Mr Fenwick said that the S3 gang was at the moment beset by infighting, which had led to death and serious injury within its own ranks.

Chief Superintedent Paul Broadbent told The Times that enforcement action was not sufficient to tackle gang crime and recruitment.

“There are a number of issues fuelling the problem, around naïvety, low self-esteem and lack of opportunity. Kids see their role models driving flash cars and having lots of money from drug dealing,” Mr Broadbent said.

“We have to break that cycle and give them something else to focus on - keep them in school, give them a structure in life. It is not just our job, it's everybody's job. To say we are just enforcers of the law is way wide of the mark. We have to work with the children's services, the schools and others to make our communities safer.”

Mr Broadbent added: “The challenge is: how do we stop kids going into higher level crime?”

Senior officers drew up the anti-gang plan in an attempt to win support for a radical new approach to the problem from Sheffield City Council and education, housing and social services agencies.

The author of the police paper says that children likely to be recruited by gangs should be viewed as “at risk” and in need of protection.

About 600 children living in the Burngreave area of Sheffield, where the feud between the S3 and S4 gangs has been fought out, have already been the subject of efforts to divert them from gang involvement.

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