From the outside, the store in Bacup, Lancashire, is unremarkable. Posters in the window announce a two-for-one offer on roast ham and baby wipes. Photocopying is available at 7p per sheet. To step inside, however, is to confront a story that divides a community and reverberates around the world.

There are four checkout desks at the store. One is regularly operated by Christine Herbert, whose teenage son was a ringleader in a brutal attack on 11 August 2007 in which a 20-year-old local woman died and her boyfriend was so badly injured that, a year later, he has still not made a full recovery.

Christine's queue is often the shortest. Many shoppers refuse to be served by her. Others, when they do, pull up their sleeves to display a black wristband as they hand over money. The bands are embossed with the word 'Sophie.'

Sophie Lancaster and Robert Maltby, 21, were set upon by a gang of teenagers in a nearby park. Robert was attacked first and as Sophie went to his aid, pleading for mercy, they turned on her. The couple were kicked, stamped on and left unconscious, covered in blood. A recording was played in court of a 15-year-old telling the emergency services: 'This mosher's just been banged because he's a mosher ... his bird's on the floor as well.' Another witness said they 'looked like dummies'.

When he sentenced the gang, the judge, Anthony Russell QC, said: 'This was a hate crime against completely harmless people who were targeted because their appearance was different.' Sophie Lancaster did not die because of her race, religion or sexuality. She died because she was a goth.

In truth, Sophie didn't like to be so easily stereotyped. She had about 20 piercings and wore dreadlocks, often dyed red. She was slender, barely five feet tall and a size eight. Both she and Robert dressed in black and were fans of bands such as Korn, Slipknot and My Chemical Romance. Their favourite film was The Crow, with its storyline similar to Sophie's own.

While rock stars have been routinely fêted as icons after death, Sophie Lancaster may be the first fan to reach this status. Only in the town where she was killed are there dissenting voices. And fear.

After she died, Sophie's MySpace site was swamped by people offering condolence and relating their own stories of being attacked for how they looked. 'I realised that prejudice and intolerance was the new racism and my hope was that what happened to Sophie would lead to a greater understanding and acceptance of all people,' says her mother, Sylvia, 52. Along with family and close friends, she has set up a campaign in her daughter's name - Stamp Out Prejudice, Hatred and Intolerance Everywhere (S.O.P.H.I.E).

In life, Sophie had been camera-shy but her name was soon everywhere: in newspapers and magazines, on websites, CDs and posters. Backstreet, the rock merchandising company, produced a range of S.O.P.H.I.E products to raise funds - T-shirts, tank tops, tote bags and hooded tops. Some people have had the campaign logo tattooed on their body; one woman videoed it being done and posted it on YouTube. Others have compiled news footage of Sophie and set it to music or uploaded artwork and poems. Dozens of groups have written songs about her. 'At first people wanted to turn her into a martyr but we didn't want that,' says Kate Conboy-Greenwood, campaign manager. 'Martyrs choose what they do but Sophie had no choice in the horrible way she died. She wouldn't have wanted to see her face on T-shirts.'

The MySpace site boasts 9,000 'friends'. Concerts and festivals have been held in the UK, United States and Australia. Branches of the campaign are being set up in Mexico and South Africa. The main motif has been a black wristband of which 12,000 have been sold. Wearing one in Bacup, however, has greater significance than showing empathy for a bereaved family or making a plea for tolerance. It is also an act of defiance, even bravery.

Kate Conboy-Greenwood, whose three sons were friends of Sophie, was amazed to hear people making remarks on local radio phone-ins such as, 'This has split the town, you know.' She says: 'So many people know [the gang's] families or know of them and they're scared. They also don't want bad publicity for Bacup.'

Isolated from major towns and cities, Bacup sits in a steep-sided valley. Much of its infrastructure is derelict despite government regeneration funding. Several shops are empty and others tatty or downmarket. The houses along the main roads are terraced but behind them, on the hillsides, are several notorious estates. 'It's a shit-hole, basically,' says Paul Mannion, one of Sophie's friends and a fellow goth; '...one of those places that needs to be wiped off the face of the earth. There might be some OK people but they're not in the majority.' On a walk through the town it is noticeable that there are few non-whites. I mention this to a local, drinking alone in a town centre pub. He smiles. 'They get fired-bombed out of their houses and given a whack with a baseball bat to make sure they get the message,' he says.

The ringleaders in the park attack were Brendan Harris, 15, and Ryan Herbert, 16. Harris denied murder but was found guilty and given a life sentence with an order to serve a minimum of 18 years in prison. Herbert admitted murder and was given the mandatory life sentence with a 16-year tariff. Three other youths - brothers Joseph, 16, and Danny Hulme, 15, and Daniel Mallett, 17 - received sentences for grievous bodily harm ranging from four to nearly six years. All five have lodged appeals against their sentences.

The five teenagers are thought to be members of a gang called the Bacup Terror Group; its BTG 'tag' CHANGE is often sprayed on walls. On members' Bebo pages (now removed) the background had yellow crime-scene tape and listed their interests as 'GBH'. Ryan Herbert had posted a video on YouTube of him rapping with three others on a track called 'Where U From (Bacup)' on which he walks towards the camera brandishing a wooden stick. Dressed in a black hooded top, he is also filmed swaggering through the town, posing at local landmarks, joining in the chorus of 'The Bacup Crew'. The song and video were part of a youth project and contained the line: 'Enough men die in this town/You mess with GBH, you go down.' It was removed from the site after the murder.

Herbert, who is known as Peanut or Razzy, never knew his father. He lived with his mother, Christine, and sister. Christine, along with parents of the other defendants, has refused to speak to the media. Locals say she is in denial about her son's behaviour. The mother of Brendan Harris, Martine Harris (also known as Martine McGuinn), is thought to have left the area; the curtains of her back-to-back terraced house in Stacksteads, near Bacup, have been drawn for weeks. The Hulme brothers lived in nearby Shawforth on a travellers' site. Joseph Hulme was bailed last year on a witness intimidation charge but the case was never brought to court. Daniel Mallett was the only defendant said in court to come from a 'good home'. He lived with his mother, Tracy, in Bacup.

During police interviews Harris admitted starting the attack, claiming he did it because he was 'drunk and showing off'. Detective Superintendent Mick Gradwell, Senior Investigating Officer, says Harris was laughing and joking with his mother during the first interview. 'The officer had to speak to Harris's solicitor to make sure they knew the gravity of the situation.' On the night of the attack Robert and Sophie had been at the house of a friend, Jonathan Smethurst. At about 11.40pm they set off to walk the two miles across town to a flat they had just begun renting. They stopped at a petrol station for cigarettes and spoke to some teenagers who were intrigued by their appearance; one girl took photographs. Robert, an art student, has a pierced lip, backcombs his hair and routinely wears make-up. Drifting into nearby Stubbylee Park, they began talking to a group of youths at the skate area. At first they chatted amiably, even sharing their cigarettes. Then the mood changed and Robert was 'volleyed' in the head by Harris before the onslaught began.

Jonathan Smethurst was the first in their circle to know something was awry. His phone sounded at 1.30am. Robert Maltby's name came up. Nothing could be heard, so Jonathan texted back to check his friend was OK. The next time it rang, 40 minutes later, a young male said: 'Have you got two friends down in Bacup Park?' The voice added: 'There's two moshers here and they look like they're dead.' The 20-year-old raced to the park to find it swarming with police. At 3.30am he was taken to Rochdale Infirmary to identify Robert. 'I recognised him but they wouldn't let me see Sophie. I just saw her dreadlocks and knew it was her,' he said.

Robert recovered but now suffers health problems including a lack of co-ordination and depression. 'I just wish that Sophie had legged it and got out of there and left me to die,' he said later. 'All I could think was, "This isn't right, why is this happening?" I couldn't see how I had possibly offended the world, the powers, to have this happen.'

Catherine Smyth, news editor of the Rossendale Free Press, believes one of the motives was jealousy. 'I think they walked into the park and were intelligent and funny and the lads couldn't stand it. They didn't like that they were suddenly getting all the attention and wanted to do something about it.' She was told that children as young as 11 were there at the time.

After the attack, Sylvia Lancaster released a photograph of her daughter's battered face, taken while she was in intensive care - knowing it would draw intense media interest. 'I didn't want Sophie to be silenced. I felt I had to do something, I had to become her voice,' she says. Before long, Sylvia, who had never before appeared in a newspaper, was interviewed by a host of publications, from the Daily Mail to Kerrang! 'I feel like I am living this mad life that I wouldn't have chosen,' she says now. 'I hate looking at myself - I think people will be sick of hearing about me. Sometimes it is a bit scary but I don't think about it too much; I just get on with it. It's all about the campaign and that has taken on a life of its own. If Sophie could see what is happening she wouldn't believe it.'

The campaign is run from a couple of terraced houses in nearby Haslingden, the work done in downtime. 'People think we have a team of professionals, but it's just a few of us doing what we can,' says Kate Conboy-Greenwood. Before offering to help, Kate had established a local branch of Amnesty. 'I have always been passionate about human rights and then this happens, right here. And to someone I know.'

Sylvia had recognised before the attack that young people adopting an alternative lifestyle were often subject to hostility. 'I was out with Rob and Sophie at KFC in Accrington and this little lad said, "There's some goths." Everyone was staring and saying, "Look at the state of them." I found it offensive and was stewing on it.' Sylvia, who works with young people advising them how to prepare for employment, planned to ask Sophie whether she and her friends would visit youth clubs. 'I thought she'd be able to show them that she was just a normal girl and there was nothing intimidating about her.'

In truth, Sophie was far from a normal girl. At the age of six she announced that she was to become a vegetarian, which she remained all her life. Three years later she was sermonising to the family on the scourge of world poverty. Sylvia, at this time, had started a sociology degree as a mature student after working in the mills and shoe factories dotted through the Rossendale valley. She remembers college friends visiting and discussing the course and Sophie 'taking it all in'. Sophie was a voracious reader, sometimes finishing a book in a day.

Through her friendship with a schoolmate whose family, according to Sylvia, was 'gothy', Sophie, in her young teens, began to change her appearance. 'She developed her own style,' says Sylvia. 'She wore a full-length black leather coat and dyed her hair black. It was just what she was. She'd always been different, a bit of an outsider. I thought she looked lovely.'

At Haslingden High School, she was outstanding in English, coming second in her academic year in the exams. 'I didn't know how good she was until I read something she'd written in a school magazine. I thought: "Bloody hell, Sophie!" The use of language was brilliant and quite powerful. It really rocked me to realise she was so talented,' says Sylvia.

Until moving in with Robert, Sophie lived at home in Haslingden with Sylvia, her father John and brother Adam, 23. Her parents separated two years ago. John and Adam are involved in the campaign in background roles; friends say family members are dealing with the bereavement in different ways. John has had an image of Sophie tattooed on his chest. 'I wanted to have a permanent picture of Sophie put there,' he says. 'It will help me to remember her lovely smile.'

Sophie and Robert had been together for almost three years. She had three A-levels and was on a gap-year, planning to study English at college. Robert was working for the summer at a local kitchen and bedroom-manufacturing firm. Paul Mannion believes the goth sub-culture matched their personalities. 'It's about having an open mind and not denigrating anyone because of how they look or if they're gay or whatever they might be. It is how you perceive life and other people.' He has been subject to violence himself. On a night out he was threatened with a meat cleaver and robbed of his wallet; his friends have been spat at and punched.

Kate Conboy-Greenwood says that about 70 per cent of people contacting her have been attacked. Mannion is hopeful the streets will now become safer: 'It's taken the death of this innocent girl for people to realise what's happening. If it makes the police change their attitude, and I think it will, that's a good thing. They have to see us as people with the same rights as everyone else.'

Talk to people in Bacup - all of whom refuse to give their name for fear of reprisal- and it soon emerges that, similar to many places in the UK, it is home to a clan of about a dozen families some of whom have been involved in crime for many years, sometimes across three generations. At the murder trial, the judge awarded £250 each to the four young witnesses who gave evidence. There have been a series of serious gang assaults in the town since Sophie died.

The Sophie campaign this week outlined its three main aims: to provide a forum for discussion; to work with youths to raise awareness of subcultures and an acceptance of people's right to be different; and to help professionals in the field.

Meanwhile, Sylvia Lancaster is rebuilding a life without Sophie. 'It feels strange at times. When people are saying "we" this and "we" that I've sometimes had to say, "Hold on here, this is about my Sophie." I've found it hard to do normal things like taxing the car and carrying on at work. It gives you an odd feeling to think how it has touched so many people. If we can save just one kid from being set upon merely because they look different, it will have been worth our while,' she says.

Sophie has been buried in the nearby town of Whitworth, where she used to walk and liked the countryside. The grave has become a place of pilgrimage. A recent visitor left a clutch of half-empty beer bottles and half-smoked cigarettes. 'It didn't dawn on me at first,' said Sylvia. 'Then I realised that whoever had been there had left the rest for Sophie.'

Sometime over the next few weeks a gravestone will be installed - a year since Sophie died. Within the family there has been discussion about the wording to put on it, how best to sum up Sophie. They've decided, finally, on a line from a song by one of her favourite groups, Rasputina:

'I'm smarter, daintier and better dressed.'

sophielancasterfoundation.com

myspace.com/inmemoryofsophie