Laura Hall looks nervously into the tape recorder. "I feel like I'm at the police station," she says. Hall knows a lot about police stations. The 21-year-old is Britain's most notorious drunk – the only person in the country with an order banning her from all pubs, clubs and off-licences. She is the poster girl for Booze Britain. Newspapers have revelled in the stories of her 40-plus arrests, her numerous assaults on police officers, her two prison sentences, the number of pints and vodka shots that will see her through a night out. Last year district judge Bruce Morgan said of her 29 drink-fuelled convictions: "I don't think I have seen a more deplorable record… A female with a record like this – it's absolutely despicable and represents all that is rotten in society nowadays."

At the pub next door to the railway station in Bromsgrove, Worcestershire, the barman tells me all about Laura Hall. Is this one of her locals? No, he says, but they know what she looks like, and what to expect if she comes in. What's that? Verbal abuse, physical abuse, the works, he says.

But Hall hasn't been drinking for six months now. She has been in rehab in Portugal, and is now hoping to make a fresh start. Although she saw doctors and a psychiatrist in Britain, she was not offered a place on an alcohol rehabilitation programme on the NHS. It was only when the private clinic in Portugal contacted her that she believed it would be possible to kick her habit.

Hall's story has been used as a parable of a country in decline, but while it might reflect some disturbing patterns among today's youth, it is also highly unusual. She did not come from a broken or dysfunctional family, she did not suffer abuse, she was not penniless or destitute. Her parents had good jobs (her father runs a building company, her mother is a health visitor), her twin sisters have no issue with drink. As a little girl she looked angelic and dreamed of being a ballerina.

Hall says it's just something in her. She first had a drink at 13, and that was it. She can't remember what she drank, just the effect it had on her. "I felt something had been turned on inside me. I wasn't scared to do anything. I was more confident. It gave me a great feeling." Yes, she got a hangover the next day, and, yes, it put her off. But not for long.

Even before she started to drink she was difficult at school. She got bored easily, and never liked being told what to do by teachers. "I've always struggled with authority. I went to school more for a social life. I do regret that now."

The drinking soon became serious. She'd go into her father's garage where he kept bottles of vodka for special occasions, help herself and replace the vodka with water. She started to truant from school, and when she turned up she'd make trouble and get suspended. Sometimes she'd have a little drink early morning, "to take the edge off". Hall had so much ability, yet by 15 she had left school without taking exams.

Her friends also drank, but not like she did. Nor did it have the same effect on them. "Some people aren't meant to drink and I'm just one of them. It's like an allergic reaction. It turns me into a mad woman, an absolute menace."

She looks anything but mad sat in front of me dressed in a black top with smart brown hair swept to the side, polite, seemingly shy and a little nervy. Occasionally, she shakes and twitches as she talks. We meet in the Travelodge in Bromsgrove along with film-maker Danni Davis who has made a documentary about Hall's life for BBC3. The options are limited. Hall does not want to meet at her parents' house and she is banned from all pubs and clubs. She sits quietly in a chair, answers every question carefully. It's hard to reconcile this vulnerable, eloquent girl with the Laura Hall of tabloid infamy – the wrecked drunk, squatting in hot pants with a glass of booze between her thighs.

She tells me what she might have typically drunk in a day. "I started off with two, three big bottles of alcopops and maybe a bit of cider. Back in the day that would get me quite drunk. Then it was Stella and vodka and anything and everything really." Was she never sick? "Oh yeah, a good few times I ended up in hospital, but it didn't bother me. I just carried on."

Drink took over her life. After quitting school, she enrolled at college to study childcare. By now her problem was obvious, and she was kicked off the course. "We'd go to college in the morning, then into town at lunch. A few pints at lunch. Well, I say a few pints, but it turned into six or seven, and obviously it's childcare, so they can't stand for that. Then I went to college again at 17 to do an admin course. I wasn't interested in it, but I thought if I can do this, I can move on to something else, but the drink was even worse there."

She insists she drank because she wanted to have a good time, simple as that. Then she stops. She knows it rings hollow. "Looking back I was blocking stuff out." Such as? "I don't know. I've always got in trouble my whole life. Always had a label. If it wasn't drunk, it was that naughty girl, the crazy girl, the one who's always stood outside lessons. I've always been known for all the wrong reasons."

'I started off with two, three big alcopops and maybe a bit of cider. Then it was Stella and vodka and anything really. A good few times I ended up in hospital, but it didn't bother me. I just carried on.' Photograph: Caters News Agency

She talks about the first time she was in trouble with the law. She was 15, drinking vodka on the streets with her friends, being loud, and the police took their alcohol off them. "But the policeman had left the car door open, so me and a few friends grabbed his hat, and walked down the high street pretty drunk wearing it. Just a childish antic." That doesn't sound very serious, I say. "Yes, but it was found destroyed because we'd handed it to a group of boys, and then we got done for handling stolen goods. That was the first. Then a few weeks later was the drunk and disorderly. We were just drinking on the street. The police came over and searched us. They took the booze away. I was off my head. I couldn't believe they were taking my drink away, how dare they, kind of thing." Was she violent? "Not violent, just mouthy. Shouting abuse." Has she ever been violent? "I have, yes. I've had fights on nights out, lashed out at my parents a few times. Lashed out at the police when they were trying to speak to me." She pauses. "I've never put anybody in hospital or anything like that."

Occasionally, her parents threw her out of home, but they always wanted her back because they worried for her safety on the streets. She says they did what they could to help her, but she was impossible. "I was a nightmare. A nightmare. Child from hell. That's the only way I can describe it. If I had a child like that, I don't know what I'd do. You're meant to love them no matter what, aren't you? But sometimes it's hard…" She trails off.

I ask where she got the money for the drink. She says she was careful, and saved from her dinner money and pocket money, she knew where to shop, and she even managed to hold down a couple of jobs for a while.

Sometimes she speaks so quietly she's barely audible. There are so many things she's ashamed of, she says. Such as? "Climbing up Bromsgrove church spire." Why is she particularly ashamed of that? She looks at the floor. "My dad seeing that – his 16-year-old daughter 100ft in the air, pissed. And I don't even know what was going through my head… and all the police stuff." She lifts an arm to scratch her head and I can see she's sweating despite it being a freezing winter's day. So much of the past eight years is a blur, and bits return to her in random flashbacks. At times she becomes defensive and says it's not as if she was going around killing people, but mostly she seems to be wishing her past away. "I've been such a drain on the police, community, ambulance, fire brigade… just lying unconscious in the middle of the road. Or lying in front of cars hoping they'd run over me."

When she was 17, she jumped off the roof of a four-storey car park. What was she thinking at the time? "Well, I wouldn't have done that sober, I can assure you. I'm not stupid. If I'd wanted to kill myself I would have killed myself." But a moment later she sounds less sure. "I was just at the point where I didn't care if I lived or died. I knew I couldn't go on the way that I was, but I couldn't see a way out. All I was doing was drinking, drinking, drinking."

She and her friends had gone to the top of the car park to drink. "Then it was time to go, my friends wanted to leave, and I was like, 'No, I want to drink more, I'm not going.' So they said 'Right we're walking down the stairs now.' So I said, 'No, I'm going down this way then.' " The fall was about 30ft. "Luckily I landed on grass. I was knocked out. The ambulance came. Then the next night I was in hospital, phoned up my friend and said, 'Hi, you coming out tonight?', and he's like, 'Laura, I thought you were fighting for your life?', and I'm like, 'Nah, are you coming out on the piss?' It didn't frighten me. I didn't think, 'Gosh, that was a close call'. I was just thinking, 'Well, my back's a bit dodgy, but I want to get straight back on it.' Nothing would stop me." Sometimes it sounds funny the way she tells it, sometimes there is a hint of braggadocio, but not often.

Most weeks, she says, she ended up in a police cell for a night, maybe two. The more pubs and clubs she was banned from, the farther she travelled, and the greater the number of police cells she experienced. At first, she would be locked up in the local Bromsgrove station, then Redditch and towards the end she'd find herself banged up in Birmingham. She often woke up not knowing why she was in a cell. She'd not only feel shame, she'd feel terror for what she might have done. "I thought, 'Oh my God, I could have killed somebody last night and I wouldn't even remember. I could have got in the car, drove, anything. I could have had sex with somebody and not known it. Anything.' "

Did she have boyfriends at the time, or was her sex life out of control? Silence. She breathes deeply and gulps and looks at Davis. "I don't know what to say. What d'you think I should say?" she asks the film-maker. Davis tells her she should just say what she wants to say. "Well, I had a few boyfriends, but nobody could cope with me. I was too much to handle." She's almost whispering. "Everybody thought, 'She's easy, she's not girlfriend material.' " Did she want boys for money for drink? "Yeah, at the time. A good few drinks wouldn't go amiss." She laughs uneasily.

As well as the nights in the cells, she has twice served time in jail – first six weeks for breaching an asbo, then early last year another six weeks for breaching a suspended sentence for assaulting a police officer.

I had heard that Hall was a self-harmer, but there is no obvious evidence. Is it true? She nods. Where was she cutting herself? "My arms." Can I have a look? "My God!" she says. But she cautiously lifts her jumper sleeves, and now it's my turn to gulp. The sight is heartbreaking – scars so intricately crosshatched you can't see any normal flesh. She can see I'm shocked. "I was punishing myself. I was just frustrated. I was doing the same things again and again, and expecting different results. It was insane. Going out, getting pissed, getting arrested, and not recognising what I was doing was killing me."

She went to doctors, who just told her she wasn't classically depressed, as if that was an answer in itself. Today, Hall claims she didn't receive the help she needed. Between the ages of 16 and 18, she saw a substance misuse worker once a week. "That was the only help I was offered because they said I was too old for the child services and too young for the adult. When I was 18 I asked probation if I could be referred to this alcohol place in Bromsgrove and they said no, you've not got the right criteria."

Why not? "I still don't know. Perhaps it's because I wasn't sat outside drinking out of a paper bag."

Eddie Clarke, chair of Worcestershire Drug and Alcohol Action Team Partnership Board and director of the council's adult and community services, says the problem is that Hall refused to engage with the support she was offered, and that after she returned from Portugal a place was provided for her at a residential rehab centre in Stroud, but she stayed only 24 hours."Throughout the period, from when she was 15 to the current day, Laura has been under the supervision of either the youth offending service or West Mercia probation service. At no point was Laura not supervised by an appropriate service." Laura's story illustrates the difficulties services can face when working with vulnerable people who are chaotically using alcohol.

Not so long ago, Hall thought she was unlucky to be alive. Now she thinks she's lucky. She's had kidney and stomach problems, but her liver isn't damaged, and she's thankful for that.

How has she managed to turn her life around? Well, she says, it's still early days, but she has to give credit to the drinking bans. At 17 she was banned from drinking in local pubs; at 18 this was turned into a life ban from Bromsgrove pubs, then last year she was banned from drinking anywhere in the country. In a way, she says, the final ban was ridiculous – unenforceable – but it did make her aware just how serious her problem was, and the subsequent media coverage led to her being offered the rehab place in Portugal.

For her 21st birthday she went to Ayia Napa, drank herself silly for two weeks and on her return went straight into rehab on 5 July. She's not had a drink since.

Film-maker Danni Davis followed Laura in Ayia Napa. "There's just an unbelievable change in her when she drinks." She looks at Hall. "You became very morbid and sad. Drink is like a switch and you are really aggressive."

Hall admits she is difficult to get to know. If even she doesn't understand herself, how can others? Both Davis and Hall's friend Sarah Hales describe her as "closed".

Hales says that in their four years of friendship Hall has never talked about why she needed to drink or cut herself. Hales's parents weren't happy when she started hanging out with Hall because of her reputation, but she says they have warmed to her. "They like Laura now. She's always been there for me. She'd help anyone, really." So long as she's sober. Hales admits the drunk Laura is a different proposition: "She's not very nice. She gets angry."

Did it put their friendship at risk?

"Yes. I didn't argue with her, but I told her I couldn't go out with her when she was drinking."

What's Hall's reputation like locally? "Mixed. Some people hate her. Some people think she's a legend, and that's not particularly helpful. Nobody should encourage her to drink."

Hales thinks that her friend should have received more help. "Drug addicts seem to get help all the time," she says, "but with alcohol it's not really recognised as such a problem."

When Hall was splashed across the tabloids, she was held up as a totem of our morally dissipated youth – ladette culture was condemned as new figures emerged showing that 200 women a week were convicted of violent crime; bars were cited where beer was cheaper than water. Under the headline Teen Vodka Epidemic, the Daily Mail reported last April that more than 100 girls a week ended up in hospital last year after binge-drinking, with 4,939 aged between 14 to 17 seen by doctors for alcohol poisoning over the last five years (compared with 1,776 boys) – an increase of 90% since 2003. Meanwhile, a third of 15-year-olds have been drunk to the point of passing out, according to research by the Schools and Students Health Education Unit.

Does Hall think this picture of contemporary Britain is exaggerated? "No, it's quite accurate. You see 11- and 12-year-olds now on Friday night. Alcohol is everywhere, cheap offers, and it's glamorised in the adverts on TV." She talks about the fruit-flavoured vodkas that appeal to teens, 24-hour drinking. "I couldn't get served in a pub at 14-15. Drinking has got so big in this country. That's all most people do at the weekends."

Hall is now optimistic about her future, but believes it is likely to be outside this country. There are too many demons here, too many people she can't look in the face. She knows she will always be a recovering alcoholic at best, but she can't believe the progress she has made. She's been back at home "building bridges" with her parents, and over Christmas she went on a trip to London with friends and had a good time without drinking. She hopes to go back to college, and eventually work as an alcohol counsellor. "I want to work with people who are going through what I've been through." She grins. "Well, nothing would shock me."

• This article was amended on 28 January 2011. Shortly after it was first launched, Laura Hall was arrested on suspicion of being drunk and disorderly, breach of the peace and breaching her banning order. She pleaded guilty and was fined £75 with £85 costs. If you need help with alcohol abuse contact Alcoholics Anonymous, 0845 769 7555.