The murder of Bobby Litambola, 17, attacked in the street in Canning Town, east London, last Saturday, brought to 24 the tally of young people under 18 who have been killed this year in knife or gun crime in London. The vast majority of these murders take place in the capital, but others have died elsewhere in the country. In August, 11-year-old Rhys Jones was shot and killed in Liverpool, apparently in error.

These children have more in common than their youth, and the violence of their deaths. Though investigations are ongoing, the shocking thing about these murders has been the fact that, in many cases, the perpetrators appear to have been no older than the victims. What might until recently have remained after-school scraps between rival groups of friends have degenerated into gang killings.

Jonathan Matondo, shot dead in Sheffield in October, came from a "respectable" family, police were keen to stress. But locals said that his killing followed months of disturbances between groups of rival young people. Jonathan's street name in this little local war game was said to be "Venomous".

Have we become caught in a disturbing spiral of youth violence, with gang culture taking over the schools and streets of Britain? Certainly, our fear about violent crime is increasing - one in six report "high anxiety" about violent crime, while 81% of pupils worry about violence against them or their friends. As to whether we are right to be nervous, however, the stark figures are not easy to interpret. In the decade to 2005, according to the Home Office, the total number of children aged between five and 16 who were murdered fell by more than 50% to 20 - and a significant proportion of those were killed by a parent. Crimes of "violence against the person" - including serious assaults and sexual attacks - have fallen by 8% over the past year. But statistics can frequently say what you would like them to say; other studies have shown rises in different types of violent crime.

What is indisputable is that young people are carrying guns and knives in increasing numbers, and are more likely to become the victims of them. The average age of gun crime victims, according to the Metropolitan police, fell from 24 to 19 in the three years to 2006. The Met says it has specific intelligence on 171 gangs in London alone, though admits that "an accurate assessment of how many there are is difficult". Some have members not yet in their teens.

Patsy McKie co-founded campaign group Mothers Against Violence after her son, Dorrie, 20, was shot dead in an apparently unprovoked attack in Manchester in 1999. She is angered by what she sees as a public debate on youth violence that demonises the teenagers involved. "Young people do this because it is what is around them. Adults need to look at what they are doing. It is not young people putting this stuff on TV, it is not young people bringing in the drugs. We all need to take responsibility."

What is frequently missing from this debate are the voices of the young people themselves. These remarkable interviews, conducted over a period of six months, display all the swaggering self-assurance and profound insecurity of the teenage years. They are tinged with bravado and a self-conscious glamorising of their own choices, but they also offer a frightening glimpse of what for increasing numbers of teenagers is a familiar way of life.

Sir Ian Blair, the Met police commissioner, has said, "We need to find out why some people feel safer in gangs than out of them." These young people may offer a clue.

Michael, 17

I arrived from Ghana when I was about 10. Growing up in Brixton was hard, my mum couldn't help me out cos she was working night and day. At secondary school I was a target to pick on cos I couldn't speak English properly. It got to the point where I flipped and anyone who tried anything I used my strength against.

I'm 17 now, and when I look back our intention wasn't to become a gang, we were just children mucking about. We grew up on the same estate, came back from school and ended up playing together. As we grew up, more friends started joining and we got bigger and bigger. Age 14 and 15 it changed. We started being lunatic; robbing handbags and phones. That's when the name starts coming up - MZ. Murder Zone, my crew. Back in the day everyone from here to Croydon and Peckham knew about MZ.

Being around people that sell drugs, I knew they were making a lot of money so I thought maybe I could do this to help my mum. So I was dealing crack, heroin, weed. I could make a grand a week. I used to use a bike cos I knew the feds [police] target drug dealers in cars.

There was a lot of us, more than 20. It's like a family. What you'd do for a little brother, you'd do for your bredren [brethren]. If one of you is going somewhere and gets stopped by someone, the whole lot of you would jump him cos he's stopped one of your bredren. If you entered their territory alone, it's what we call "slipping" and you can get hit. So when we went out it was as a family - MZ family, we used to call it. If one of my friends gets hit I'm down to do whatever it takes. Let's say he gets beaten up, that means I will go over there and do the same to the youth. I won't murder them, but I'll beat him till he's unconscious, just like how my friend's unconscious. But if he's murdered my friend, that's a different story. If you've lost a friend, most people my age would think they had to take a life from the other side. Either because of the rep you need - "Yeah, he pulled the trigger he was a bad man" - or cos he was your bredren and you can't let a life go away like that.

At first I was a younger, a "buck". You look up to the big boys, their names are known, they're bad and no one wants to mess with them. You see the jewellery, the fast cars, the fast women, you've heard about their background and you're thinking, "Rah, they've done it, so why can't I?"

MZ made life simple for me. Their reputation made it safer for me to go round certain places. You need to protect yourself if you're leaving your estate. In this generation everyone's trying to rep their own little postcode. It's like with lions. When a lion's got his territory, he don't allow any other male to get through. If the male comes for me, it's a fight, it's a war right there. They just think I need to control my territory, otherwise another male will try and come and take over. If you get caught slipping by another group of boys, then you're going to get it dangerously. It's about who's more powerful than who. That's why people kill each other.

I've had a friend dead. He was killed in Kennington, knife to the heart. There are plenty of knives on the street. I've been sliced on my neck - it was just a little scuff, someone pulled a knife, reached for the back of my neck and just sliced it.

Most of the boys I know have either had a bullet or a knife. I've been shot. I was hit on the arm with a bullet by being in the wrong place at the wrong time. We'd gone to a party and my mate saw an enemy and punched him, we ran off and they started firing after us. I didn't really feel anything until someone told me, "Your hand's bleeding", and then I realised, "Rah, I've been hit." Luckily it wasn't hard enough to go through my bone or I wouldn't be able to use my hand no more.

Disrespecting someone is major these days. When I was growing up, if you disrespect a man you're going to have to rock him one on one with your hands. Now it's about shooting. More young people have got guns and they think it's easier to kill than fight.

Tupac made me change my life around. I don't care about 50 Cent or any other rappers, but he was different. People didn't understand 'Pac, but if you really listen to the guy and his behaviour, there was a meaning to it. I'm not fully out of this yet, but I want to be. It's not like you're going on holiday and you can just pack your bags and go. Imagine you're living this life for eight years. That eight years has made you what you are today. You can't resist that background.

I'm doing A-level art now and I'm hoping to go to art school. I want to write films. I look to [British rapper] Asher D. He's been through similar things. He's been stabbed in the back of the neck like me. He nearly went to prison for firearms. That's why I give him respect. For flipping round. I hope I can do that.

Danny, 17

We started PHC after what happened to my best mate. It stands for Paki Hating Crew. He was murdered three years ago by a group of Asians from the other side of Leeds. I remember the night he died. He was chilling on the estate with two mates and I was just round the corner playing football. We saw about 40 or 50 Asians running off and knew something had happened. We sprinted round to see what had happened and his body was lying there on the pavement. The police wouldn't let us through to see him. His body was covered up but you could see a load of blood on the road. They'd stabbed him and beaten him with baseball bats. His mate told me they were beating him so hard his body was bouncing a foot off the ground. But he was still alive when we got there and I thought he'd be OK. Later on that day his mum told us that he'd died in hospital. We were shocked. He was only 16.

He was a big lad and used to take on six or seven of them at a time with his fists. They hated him. That's why they came for him in a big group. It took 30 grown men to get him on the ground. They wanted to get him, but they didn't want to kill him - they fucked up. If the police hadn't found the killers and sent them to jail, they wouldn't be alive now - we'd have made sure of that.

We used to talk to the Asians, but since then it's never been the same. They started their own gang - WBHC, the White and Black Hating Crew.

People who think we're racist are wrong. My mate was mixed race; there's black people in the gang and in my family. I've got no problem with black people, Chinese people, even most Paki people are all right. But those Asians who killed my mate, I'm racist towards them.

PHC has grown and grown, there's about 50 of us here and this is where it started. But if you go round the city you'll find different groups in PHC. There's no leaders, we're all the same, everyone's their own person. There would be about 500 of us, if we ever all got together. They'd be fucked, but it hasn't happened.

Leeds is all I've known. My mum and dad split up when I was six and I live with my mum. I got permanently excluded from school at 15 for drug dealing. I could make £100 a day. I've also been tagged twice for street robberies. We'd do it together, me and the other lads in the gang, taking mobile phones, bikes and money. We could make a few grand a week and would share the proceeds. I used to spend the money on weed, clothes and food. I got let back into school because no other place would have me. School was shite, I hated it.

The government talk about stopping gangs. Well, give us some shit to do, then. There's nowt to do round here. There are fights every so often. People bring weapons but don't always use them. I've been hit with sticks and bats and bottles thrown by the Asians, and we've done the same to them. I've seen guns. One of my mates who's 14 has got one, a revolver and bullets. He was messing about with it once and fired it through the floor. You don't really need a gun round here, but he says it's for his own protection. I don't carry a knife normally, but I might take one if I'm going up there to the Asians on top of the hill. The fighting used to be exciting. But I'm not really into it any more.

I'm always being stopped by the police for things I haven't done. They just go for a face they know. I've been in custody for five months but I could have gone down for three years for the street robbery. That made me change. The judge said that if he ever saw me again in that courtroom I wouldn't be going back home. My mum pleaded with me and said that if I didn't stop I'd be in and out of jail for the rest of my life. I haven't been in trouble for a while now.

I left school last year when I was 16 and went to college. I finish my apprenticeship next year and I'll be able to work. What do I want from life? To settle down, and move away from this shitty place.

Claudia, 18

I've spent my whole life in Brixton. Nowadays you see people with weapons on the streets all the time. There's plenty of machine guns, but mostly young people have got replicas - often they're too scared to let it off because it could backfire.

When you're involved there's a lot of people that hate you so you need to have protection - it might be a group of people, or you could be in a gang. I'm involved but I don't see myself as in a particular gang. The most that a lot of us will say is that we're from Brixton - that's it. Gangs change too much every day.

Peckham and Brixton have been in argument from God know's when. Peckham will not be caught in Brixton and we will not be caught there. I don't trust Peckham, full stop. You can always spot a Peckham boy, when you've grown up in the ends [area] you just know - the way they look, the way they walk, the way they act, you can just tell what a Peckham boy looks like, just like you can tell what a Brixton boy looks like. Peckham wouldn't come here without guns. There's no neutral ground, but the closest there is to it is Brixton KFC, because the police are normally wandering up and down.

I got involved because I needed the money. When I was 13 I got kicked out of school for fighting. The following year I left home. I was renting a flat by myself, which was costing £100 a week and I had to provide for myself. I was dealing crack, heroin, everything. A lot of people will say they're doing this for the money and a lot of people ain't really taking the money. But for me the money was great.

There is peer pressure, but you don't have to be involved. Most of these crews that keep appearing in the paper aren't making any money. It's just about status. But a lot of young people don't realise what the risk is. They've been kicked out of school, mum works 24/7, there's nothing for them to do. That's how it always starts - boredom.

I got involved because I wanted big, I wanted the quick route to money, and it worked for me. I was not pressured, no one forced me, and it was fun, there's a thrill to it. The money's live [cool], everyone's live, no one can talk to you or give you shit, it's a good life. I'm a girl! Getting that type of money as a girl of 15! You can hold yourself, no one can rob you, no one can move to you [mug you], it feels good because of who you are, your reputation.

There are girls moving in crews, but there ain't many doing what I did. Because when boys are beefing I'll be involved as well. They said to me once, "She makes money like she's a boy, she bangs it out like she's a boy, so she can get taken out like a boy." It's true what they were saying and I need to watch out all the time. Brixton's my ends, but I've still got to keep on point because I've got a lot of haters.

I've seen too many shootings - the first one was when I was 13. In the past three years I've nearly been shot about half a dozen times. One time they put a gun to the back of my head. I heard them cock it, but it jammed. I turned and I hit it out of their hand - bang - it dropped on the floor. It was just me and a mate, there were six of them. They could have grabbed me but I think they were more shocked at what just happened. A youth picked it up. I looked at the boy who had the gun, punched him in the face and then I jumped in a car and got away. I could be dead, I know that.

Another time, this guy was pointing the gun at me, but while he was talking I managed to wrestle it out of his hand. Later I got revenge. I'd rather not say what we did to him, he got enough to last him a lifetime. You can't pull a gun on somebody and then not shoot them, it's like putting somebody in a coffin and not burying them.

I've pulled a gun a few times - I had to, they were shoot-outs. Everyone had guns, they pulled, we pulled, shots were let off but no one got hurt, although I don't know how.

If my dad was around I don't think I'd have done any of this. He died when I was young. I wouldn't say I'm totally out of it yet, but by next year I'll be out of it altogether as it's not a good life to stay in. I plan to be very wealthy and I won't be living here. Next year I go to uni to study business and law and I ain't got time to be putting my head in nothing else but uni. I'm very ambitious - I want to do law and be in property. We live in a racist society, but I believe you have to make your way to the top and change things.

Marlon, 16

My life was basically surrounded by gangs because Walworth Road was a dangerous place to be - we were at war with Peckham. I started acting like a gangster at primary school when I was nine. I was being rude to the teachers, beating up the teachers, using obscene language and not listening.

I joined Walworth Road Gangsters at 12, when I started secondary school. There were 30 of us. Some of the gang were there because their families neglected them and they needed people to turn to. It starts with you bonding with a close friend, then you maybe meet other people until you just come together as one group and think, "We're a family." If something troubles our minds, we'll go and sort it out, that's how a gang is.

We carried baseball bats, lots of weapons, knives... we never carried guns, but we could get hold of them if we really wanted them. There was lots of guns around from the olders who used to watch over us. There was olders and youngers and tinies - we were the tinies back then. Each person in a group had to do different things.

Olders would ring up my cell phone and set me tasks like delivering drugs and collecting the money. I'd get paid £500 a week and hand over about five grand to the older. I used to look up to them. They had what we didn't have - cars, rings, gold chains, money, lots of girls, so we thought, "We want to live like that."

Later on, I was a leader who gave the orders. Every so often people would refuse to do what I told them. At that point you have to go and beat him up to gain their respect again - that's how gang culture works.

We weren't allowed in Peckham, Peckham weren't allowed in Walworth. The border was Burgess Park. If you were on your own, they'd beat you up, and the same thing with us. So I had to stay out of Peckham. It was like a war back then, but I'm OK now, I can go down there.

We used to put a lot of people in hospital, hitting them over the head with baseball bats. It's the easiest weapon - you can just carry a tennis ball and say you're going to the park. And if you want to, you can kill someone with a baseball bat. I knew lots of people from Walworth Road who lost their lives. I remember a girl called Ruth who was stabbed two years ago over drugs.

When I was younger, you used to have a scuff and then shake hands. Now people say if the next man steps on your shoes, you'll shoot him for it. Fights are never over now. You may think you've fought and everything is sweet, but someone can just go and shoot you now. It makes me sad to see the tinies shooting people over nothing. In 20 years they'll probably either be dead or in prison for life.

My dad died when I was three and I grew up with a single mother. She couldn't cope when I was in Walworth Road, she had to get other family members to talk to me. School didn't know what I was doing, they thought I had behavioural problems - Tourette's, that kind of thing. But the problem was the people I hung around.

The Walworth Road guys are still doing what they do. I can't neglect them and say, "You're not my friend", but I don't follow them any more.

The youth project where I am now treats me like a man and makes me feel part of the family. I've decided I want to be a football coach and a construction worker.

I started questioning the gang thing to my friends, but they didn't respond. In the gang some people are achieving something, making money, and some people are not, and you'll never know who's achieving something until it's too late. After a while you realise this is childish, just seeing someone on their own on the street and beating them up.

They have to sort the police out - the guns are coming into the black community from corrupt policemen. There needs to be more youth projects, too, for the people who feel neglected. And there are no male role models in school. If a woman teacher was talking to me, I'd think she was taking the mick out of me. But if it's a man, I'd say, "Yeah, he knows what he's talking about, he's probably been through it."

David, 19

The first person I saw commit a murder was my dad when I was seven. In all I've seen around 15 people murdered. Dad used to try and keep me away from it, but sometimes he couldn't get anyone to look after me. I don't know what that first one was about. He did it with his hands - he used to beat people to death. And after a couple of times you become used to it, it seems normal.

I was born in England, but my mum's Argentine and my dad's half Jamaican and half English. I grew up in south London, mostly in Peckham, but have moved back to Argentina twice, when I was three and 15.

I started out in a little estate gang in Bermondsey when I was about eight. I was the youngest and I learned to defend our territory. I used to fight people, walk around with a cricket bat - it sounds funny, but I didn't know about baseball bats then. I had no reservations about hitting people, we had a rottweiler, we had dobermans and would take them for walks and frighten people.

I got myself a little reputation in my area and when I went to school in Blackfriars it got bigger. I was exposed to people from different areas and joined a north London gang, even though I am from south London. There were a couple of other gangs in school, so it was best to be in one yourself. Aged 13, we took guns into school, knives, one boy took an axe, all kinds of things, dog chains, whatever we could get our hands on. The guns were pistols, converted replicas. I never used them, but I'd pull it out, which was enough.

Outside of school I've done loads of shootings, both here and in Argentina. I went to Argentina when I was in my mid teens. I lived in the capital for a while and then moved to a small town outside. It's just a poor country, it really is like people will kill you over nothing. I used to shoot loads of people - it was all to do with cocaine and my main job was to collect debts. If they didn't pay I had to torture them, anything to make them pay. People knew me and crossed the street to avoid me, which I thought was respect, so I was happy. Really it was fear.

In England the gangs thing is mainly associated with black people, but that's not the case. The gang members I worked for were Latin - Colombians. It's not really about race - these poor communities are separated; people in Peckham live just three miles from Westminster, but look at the quality of life. It's almost like they've made a decision, "I want a piece of the pie" - these young gang members are some of the smartest, most polite, funny kids you could meet. They don't want to have to go out and be violent, but that's the only choice they think they've got.

Violence is good, but after you get exposed to it so many times, it gets dull. With shooting someone, the pay-off is the explosion, the bang, the flash - it's almost like fireworks. You don't see blood splatter everywhere like in the movies, though. I don't know if any of my victims died, but I used to make sure I did damage. The intention was to leave a scar on their face to show I'd been there. My best friend taught me to go for their armpit as it's a hard place to heal up. If they've got stitches they're going to rip open, they're really going to feel it.

The other day they stripped someone naked and made them walk through Peckham High Street. If you don't want that kind of thing, then you need to earn the respect. How did I get the respect of the north London boys? You have to be the cruellest, the most violent, the most intimidating. You don't even need to use brute force. Sometimes it's mind games, spreading stuff about them within their gang, intimidating them over the phone. Text messages do get used. But people are getting more aware that there's a record of your text, it makes more sense to use a pay phone or something that's harder to trace. I had to get a few people who weren't showing me enough respect. A boy I was friends with borrowed a CD and one of my shirts and didn't bother to give them me back. So I broke into his house and stabbed him while he was asleep.

I got out of it because I was given a chance. I was raised all my life to think I was worthless. But then when I was living in a shared house there was a family from Mauritius in the next bedroom. They knew I wasn't really all right. They took me to a South American church and that's how I learned a lot more about morals and remorse. The pastors helped me a lot.

If it wasn't for this family I probably would have ended up falling back into it. A lot of middle-class people think that gangs are untouchable and youths are unreachable, but that's not the case - these 13- and 14-year-old boys are scared, they are looking for guidance and they're going to anyone who can provide it, whether that's a 30-year-old gang leader or a 20-year-old church member. That's why I love the family. They couldn't even speak English, but they still managed to help me. They took a chance and said, "I'm not going to judge you." I think that was one of the most inspirational things.

Becoming a dad has had a great impact on me, too. My daughter's a year old now, so I'm no longer responsible for just me. I want her to avoid making the same mistakes I made.

· All names have been changed.