One ex-gang member describes how her life was taken over by a boyfriend, and how the cycle begins at school

Lisa remembers the moment she knew her life had been overtaken by the gang. Her boyfriend of six months had called and asked her for a favour. Half an hour later she was in the kitchen of a small flat in north-west London looking at 2kg of crack cocaine.

"It all starts with, 'Babe, can you just help me out.' Then the next thing you know it turns into your job. But you don't get paid. It's the kind of job you just do and shut up." With two other girls she was told to smash up the raw drugs, weighing portions out before wrapping them in cling film.

She said that as they worked in silence there were always two boys smoking cannabis, who watched their faces and hands "making sure they didn't fuck up". Other boys would come and go to make deliveries.

"It's the girls' job to cut up [the drugs] and the boys' job to deliver," says Lisa, who is now 19. "Occasionally other girls knock on the door and offer blow jobs to the boys and then smoke a rock in the kitchen as an exchange."

The flat had been turned into a "traphouse" and Lisa's then 16-year-old boyfriend, Jerome, led the operation. Four years on and Lisa admits this still sounds like the stuff of American crime shows. "You can't make much noise and you don't chat unnecessary shit," she remembers.

Last Wednesday the Metropolitan police launched an initiative to crack down on the rise of gangs amid a sharp rise in serious youth violence. Central to the scheme will be an attempt to help young people escape gang life.

But Lisa reckons it will be harder than the authorities think to break the hold gangs have across large parts of the capital. "It is getting worse," she says. "It starts at secondary school … it's a cycle."

From an early age Lisa says she was aware of gang rivalries, realising that people from an estate a few hundred yards away were considered deadly rivals.

But she says it was not until she moved from junior school that she began to be drawn in. "When you start secondary school everything's new because you're mixed with the older kids. You mix with Year 11s and you don't want them to bully you. So what you do is you put up a front. I'm little but I'm also bad. And you basically get ratings, respect from your peers.

"Start with answering back to the teacher and you'll get a little bit of respect; thieve something from the shop, get a little bit of respect; rob someone, you'll get a little bit of respect; punch someone up, you'll get a little bit of respect, until eventually you're in it so deep you don't know how you got there."

However, it was not until she began a relationship with Jerome – a well-known gang member – that she acquired her "pass".

"If you have a boyfriend you'll be automatically gang-related. I was in a gang because of my boyfriend. I wanted to get off with a bad boy, it was a thrill. No one can touch me if I'm going out with him. It was that. Young people think, 'If I'm in a gang no one can touch me because I'll have friends to back me up.'"

The couple met at a youth offending service. He had been committed of knife-point robbery and she had been found guilty of common assault. To begin with she had a "normal" relationship. "During the first six months he was building up trust. I'd go and see him but nothing major [happened]. Boys are paranoid, they think their girlfriends will set them up."

But he began asking her to "help out". At first it involved taking messages, then she was asked to help cut up the drugs. She knew things had changed. "That's when I got dragged in."

Soon Lisa was carrying drugs and weapons . "In my eyes it was normal because I was just helping my friends out." She would drop off packages which included ferrying Jerome's gun. "It never crossed my mind that if I'm walking from A to B anything could happen in the middle. If I got caught [with the gun] I would have said no comment and took the bird with me."

The relationship with Jerome continued as she was drawn deeper into gang life. "Boys can work a girl out, fold her up and put them in their pockets. You don't love him but you're made to believe you do.

"You're made to believe that it's a way of life and that's as good as your life will get. It's all very fiction, but it's not real love … you don't realise how deep you're in until it's too late."

As she got to know more people in the gang she realised everyone – boys and girls – had a different role. "There's what's called a hood slag, it's the girl who's not anyone's girlfriend, however she fucks with every boy.

"There'll always be the boy who no one fucks with because he's a madman, there'll always be a beg friend, a boy or girl that isn't really down with gang violence but want to be one of the cool kids, there'll also be a pagan, a snake, who's known to have some connection to the other side.

"Then there is the baby mothers, the wifeys, the crack heads, a posh girl that wants to fuck a hood, and there's always a traphouse."

As Lisa became more embroiled with the gang her life became more dangerous. "There were areas I couldn't go into because of him. I couldn't go to my mum's house and when I did see her she had to meet me somewhere. If I was seen by myself something would have happened to me."

When Lisa turned 17 her endless nights spent in the "traphouse" began to take their toll. "What I was doing started to become awful. I didn't want to do it towards the end. But I was more scared because that's when people turn against you. You know everything in the area. Who's selling drugs, who's got firearms."

Lisa began to realise the extent of the violence and criminality she had witnessed over two years. "I've seen people get dragged out of their cars and beaten up because they're not meant to be in that area, I've seen people get shanked [stabbed]. Boys would get a pitbull and train it to bite, they'd batter people, rob them for their watches.

"It's not nice but at the same time you don't say anything because you don't want that to be you."

Instead she tried to slowly extricate herself from the gang. "I started saying I'm busy but there was peer pressure. He'd tell me I wasn't being a good girlfriend. You feel obliged. Some people have a breaking point, others don't."

Then she became pregnant. "Don't forget I am madly in love and I told him I am pregnant – he said, 'Get rid of it' … We had an argument and he hit me, for the first time, he smacked me down."

When Lisa went for her abortion two weeks later she had already miscarried. "I was really upset but in his eyes it was nothing. I was with him for another three months and he kept hitting me and throwing stuff at me."

Lisa was certain she was not about to make the same mistake as her mum, who had put up with domestic violence for 10 years. "I thought fuck that, I'm not staying for this."

By now Jerome had moved away London after getting shot. She moved into his new house but realised she had reached her breaking point. She left clothes and other belongings there to avoid suspicion and walked away, changing her mobile number and deleting her Facebook account.

The pair have not met for two years but Lisa says that her old life still catches up with her. "It's not easy at all. I had his friends coming up to me saying if I opened my mouth I knew the deal. People telling me where my mum lives. Two years later it's still there."

Lisa believes that university will be her ticket to freedom. With areas of London still off limits and people she cannot talk to, "it's always going to be like this unless I move out."It's a choice. But it's a hard one. If you get out you consider yourself lucky."

All names have been changed