Teachers and schools are being asked to share their experiences of gangs as part of a major study to find ways of preventing the spread of violent street groups.
The research, commissioned by the NASUWT union, will be used to create a toolkit to help teachers tackle gang-related problems in their area.
Earlier this year, the first part of the union's study found that teenagers were becoming involved with gangs at a younger age. It cited examples of former pupils being killed as a result of involvement in gang- related activity and said a secondary school in an affected area might have 20 pupils seriously involved in gangs, 40 with a less serious level of involvement and up to 100 with a marginal connection.
The first study was restricted to London and the West Midlands, but the union now wants to know if gang culture has spread; how many teachers have concerns; if it is affecting their work; and what measures they are taking to prevent it.
Chris Keates, the union's general secretary, said the aim of the second survey was to get a better idea of the effect of gangs on schools. "Now we want to know more and we particularly want to focus on the behaviour and intervention strategies schools are using," she said.
The extent of teenage involvement in violent crime is far from clear, with many studies contradicting one another. For example, police and Youth Justice Board figures show the number of first-time entrants into the criminal justice system and in custody has gone down - mainly due to changes in government policy - but surveys of young people show the number admitting to illegal activity has risen by 20 per cent, with a 43 per cent rise in violent offending.
Previous NASUWT research said many young people were groomed to become gang members, particularly by older siblings and friends. It also found a clear link between violent crime and the belief of the offender that they were acting in self-defence.
Kate Broadhurst, head of research at the Perpetuity Group, which is carrying out the study on behalf of the union, said the age of those being recruited into gangs was falling: the number of under-16s has doubled.
"Many get involved to have a sense of identity," she said. "The gang replaces something missing, which they find on the street, and this seems to give them self-esteem. Many refer to gangs as their street family."
The group's research shows that the longer a young person is a member of a gang, the more difficult it is for them to leave. And members are five times more likely to admit to carrying a gun.
Speaking at a fringe meeting of the NASUWT conference last week, Patrick Roach, the union's assistant general secretary, said it was important for teachers to look outside schools for the roots of bad behaviour because the classroom remains a safe haven.
But he said some teachers were having difficulty in accessing services from other bodies, particularly mental health professionals.
To contribute to the research, phone Amy Burrell or Michelle Duffin on 0116 222 5565.
Safe havens at risk
Schools remain a "safe haven" even if their community is blighted by gang violence, a study for the NASUWT by the Perpetuity Group has found.
But some gangs have the "potential to infiltrate" schools. The location of a school and its catchment area determine how much it is affected.
It is still not clear why children take weapons into school, but researchers believe pupils feel threatened while travelling there, particularly if they have to walk through an area outside their home environment.
Other reasons for joining gangs include poor parenting, lack of positive role models and an absence of diversionary activities in the community. Some of those interviewed also told researchers about the perceived glamorous lifestyle of gangs. For some, involvement in gangs was a natural consequence of living in their community; for others, it was the result of family connections.
The study called for teachers to admit problems with gangs, where they existed. It also called for more education about gangs in schools, including a visit to jail to demonstrate the realities of prison.