One contact with inside knowledge speaks out. His voice has been changed to protect his identity.
By Angus Stickler
On 1 January, Henry Bolombi - or Black H as he was known - was stabbed to death. He was the first of 27 teenagers killed in London this year, the victims of gang crime.
The Today programme has investigated the gang culture in Edmonton, north London - and has uncovered a world where violence and revenge are rife.
Black H - Henry Bolombi - was stabbed at an Edmonton bus stop
Three weeks after 17-year-old Henry Bolombi was killed, Louis Boduka - or Usher - was stabbed through the heart. In February, 16-year-old Iyke Nmezu was attacked and died in hospital. All three were reported to be members of a gang.
This BBC investigation has been told that there are two main gangs operating together in Edmonton: one is Dem Africans or the Green Gang and the other is its cadet force, the Grey Gang or Grey City.
And one of the ways they communicate is on the internet. In an examination of more than 125 social networking sites, we identified scores of gang members.
Video clips taken on mobile phones and posted on various sites include, for instance, a picture of young man stripped to the waist, wielding a knife. He slaps an eight inch blade into the palm of his hand, issuing threats: "You mark me, I'm gonna catch you...blood clot, that's what I'm saying...going straight through ya belly."
The names of the three murdered teenagers come up again and again - as do threats. "It ain't over…someone is dying on behalf of Usher…keep watching the news…revenge is sweet - trust. Dem Afrikanz DA all day."
And another: "Love to all my restin family - Black H - Usher - Iyke. Believe me it's not over."
It mirrors real life on the estates of Edmonton. On New Year's Day, 18-year-old Henri Bolombi was stabbed to death.
You get less sentence killing some one with a knife than using a gun - so what's the point?
Speaking to gang members is not easy. One contact who we met was later accosted in a park in the heart of Edmonton and was warned from speaking to me, after a gun was held to his head.
Another gang member with inside knowledge was prepared to speak, because, he says, the violence has escalated out of control with too many "boys" dying. He says the threats made by gang members to avenge the killing of fellow gang members should not be taken lightly. "I will say it's something - more of a promise," he says.
The gang operates in clearly defined postcode boundaries - N9 and N18 in north London. Tottenham to the south contains rival gangs; as does Walthamstow to the east.
A rival gang member from Walthamstow says he became involved because, growing up on an estate, each person needed protection.
"If you're getting beaten up and you're not part of them, you won't get help or nothing. If you're a nobody, nobody will respect you."
Louis Boduka was known as Usher and was stabbed through the heart
And like Dem Africans, the Walthamstow gang is organised. "I worked my way up. And what you do and how you are - the more stuff you do the more ratings you get."
The "stuff" includes robberies and stabbings. "When you're vexed and pissed off...someone done something to you - and you remember what they did, you just want to get them back - you don't really think about it, you just do it."
He also was entrusted with one of the gang's guns and knew that his gang was involved with a shooting.
But the insider in the Edmonton gang explains that knives (or shanks) are, more often, the weapons of choice.
"You get less sentence killing some one with a knife than using a gun - so what's the point?" he says.
"It's less trouble - less noise and you can easily get away because nobody really wants the commotion around them. A shank is a more better way of actually getting rid of somebody."
He also explains that what is being fought over is money, drugs and territory. "These are actually good business people, you know.
The green paint means that the sign has been tagged by a gang
"Selling drugs you have to be a business man because there is a lot of dealers but there's not a lot of buyers."
The Metropolitan police deny that the gangs are out of control. Commander Simon O'Brien is responsible for policing an area covering 11 London boroughs that includes Edmonton.
He says that the police do not want to see young men and young woman losing their lives, and that their policing is having a significant impact on crime rates.
"Our stop and search activity has been highly successful," he says.
"We are denying the ability for certain young people to carry knives. In the vast majority of cases, young people live a good life."
But on the streets, there is little optimism that the violence will end. Carefully organised, with a hierarchy and rules, the gangs also offer a form of security.
As the gang insider says: "Anyone whose actually been involved in a gang will tell you you get the love and the affection, you get people, who - as we say on the street - people that's down for you."
And he says there is no end in sight to the violence. "These people are recruiting every day. They are getting wider, wider, wider. You'll just get growing numbers of gangs, growing numbers of killings, growing numbers of drugs, you know. You tell me what that's going to lead to - you know, it's going to be a dog eat dog."
You can watch Angus Stickler's full report on gangs on Newsnight on Thursday 11 December at 2230 GMT on BBC Two, or catch up on the BBC iPlayer.
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