Social networking websites such as Bebo, YouTube and MySpace have been identified by police as having a big influence over gang culture and youth violence.

Teenage gang members across Britain are using online forums to bait each other and to brag about their use of knives, guns and drugs.

The Times understands that police are examining possible links between online activity and several teenage murders in the past two years.

The number of teenagers who have died violently in London this year reached 26 at the weekend, with the stabbing of Oliver Kingonzila, 19, in Croydon. The death toll is the same as the total for the whole of 2007.

One previous victim of the violence in London, Shakilus Townsend, 16, was pictured on Bebo posing with a knife. In July he was beaten with a baseball bat and stabbed repeatedly after allegedly being lured into an ambush by a teenage girl. Some messages on a tribute website set up for Shakilus described him as a “fallen soldier” while others carried death threats for the girl who allegedly invited him to meet her.

“We are looking at a whole new area of open-source intelligence,” a senior Scotland Yard source told The Times. “It has a part to play in a number of inquiries. But these social networking sites may also have a role in predicting incidents and helping us prevent them.”

Detectives have struggled with their lack of familiarity with the networking sites and teenage slang. In Scotland, Strathclyde Police have sought to solve this problem by using cadet officers to trawl the internet for information about local gang members.

Cadets involved in Operation Access, which began in July, have found pictures and videos of youths holding weapons, and the inquiry has already resulted in five arrests. Assistant Chief Constable Campbell Corrigan, speaking after the arrests last month, said: “It seems that many of these sites are offering youngsters an easy, accessible facility for them to boast [upon] about their involvement in gangs or the collection of weapons they own.

“We will continue to monitor social networking sites as part of our campaign against violence. This type of behaviour is completely unacceptable and, with Operation Access in full swing, we hope that people will think twice about getting involved in these types of activities in the first place, let alone continue to post images or footage of themselves carrying weapons. The reality is that it won’t go unnoticed and anyone involved in this type of behaviour will face serious consequences.”

South Yorkshire Police have also looked at networking sites in their efforts to stem an emerging gang problem in Sheffield. One video posted on Bebo by members of a so-called postcode gang in Sheffield that calls itself the “S6 Mafia” features youths posing with a stab vest and baton bearing the force’s logo, both apparently stolen from a patrol car.

Some of the tactics police are using derive from the work done by the specialist units that tackle internet paedophile rings and monitor terrorist and extremist activity.

Gloria Laycock, director of the Jill Dando Institute of Crime Science, in London, said that more research was required into why some young people carried weapons. “The messages that young people get influence their behaviour and they get a lot of those messages from social networking sites and the internet,” Professor Laycock said. “They are very susceptible to the message of following the crowd . . . It is worth looking at how we communicate with young people and how they communicate with each other if we want to exert some control over their behaviour.”

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