Errollyn Wallen's 'Anon': Manon Lescaut for the 21st century

Errollyn Wallen's compositions give a voice to the voiceless. Her latest is about female murder victims

On song: Errollyn Wallen

When Errollyn Wallen was 17 she was nearly murdered, more than once. She and a friend were hitch-hiking around Europe; several times, she says, men who had offered to help them then drew a knife. Apparently policemen too. "We managed to escape each time," she says, "but we were young and naive and hadn't known we were in danger."

That experience has fed into Wallen's latest opera, Anon, the London premiere of which takes place on 26 July in the Tête à Tête Opera Festival, the vibrant annual celebration of new opera which has a new base at Kings Place and the Platform Theatre of Central Saint Martins. The story is modelled on Abbé Prevost's 1731 novel Manon Lescaut, concerning a young girl torn between true love and the pursuit of wealth; arrested and deported for prostitution, she dies helpless in an American wilderness. Both Puccini and Massenet transformed the tale into powerful operas. Today it remains horribly relevant.

"I hate that story," Wallen says. "But it shows how easy it is to get into trouble if you don't realise that people around you might be predatory. Almost every day there's something on the news about a young woman being murdered, abused or exploited. Mostly, their voices go unheard."

Giving a voice to the voiceless has been a recurring obsession for Wallen – and perhaps it is no coincidence that her own voice as a composer springs from one of the least represented backgrounds in British contemporary classical music. She is the UK's first internationally celebrated black female composer, and thus a figurehead for a whole new generation.

Now 56, she has been recognised with commissions for the Paralympics opening ceremony in 2012, besides the Royal Opera House and the Philharmonia Orchestra. She was awarded an MBE last year, has won an Ivor Novello Award, teaches at Trinity Laban Conservatoire of Music and Dance and is composer-in-residence at Birmingham Conservatoire, where her students have included the singer-songwriter Laura Mvula. She would dearly love to see a greater ethnic mix in the British classical music world. "Classical music in this country does tend to be rather 'pale' in orientation," she says, with a twinkle. "It's not like that in the US."

As creator of an eclectic personal style that transcends barriers by simply refuting them, Wallen is a true original. She cuts a distinctive figure, too: gold-frosted curls, glittery eye-liner, bright trainers. Was she not short of role models when she was starting out? "My role model was JS Bach – for his music and his attitude to hard work," she declares.

Creating music absorbed her even in childhood, before she knew that being a composer was an option. Wallen arrived in London with her family from Belize when she was two; here, she and her three siblings were brought up mainly by an uncle and aunt while their parents moved to New York. "The idea was that we'd join them eventually, but somehow it never happened," she recounts, "so it was almost as if we had four parents." Her family remains close: her brother is the trumpeter Byron Wallen, one sister is a nurse and the other works with young offenders in New York. But composing can be a solitary activity: "When I was about nine, I realised that I didn't fit in with the other kids at school. I remember thinking that whatever I did, I had to make sure I could do it on my own," she says.

Sent to boarding school, Wallen was disappointed not to pursue her first dream – becoming a ballet dancer. "My parents said: 'Don't be silly, we've never seen a black ballet dancer,'" she remembers. "I comforted myself by playing the piano all the time. One day our history teacher came in and he said, 'You play very well; maybe you should consider becoming a composer, because there aren't many women composers around.' That planted the idea."

Studies at Goldsmiths College and an MPhil at Cambridge followed; and soon her musical reach extended from popular songs to orchestral works. Early in her career, she started her own group, Ensemble X, with the motto: "We don't break down barriers... we don't see any"; last weekend her Errollyn Wallen Ensemble went to Latitude with Cautionary Tales, based on the rhymes of Hilaire Belloc. "I want to bring opera to wider audiences," she says.

Anon aims to do that, too. For this co-production between Welsh National Opera and the Birmingham-based South Indian arts organisation Sampad, Wallen says her brief was to create an opera for a teenaged audience about the exploitation of young women and girls all over the world today. She therefore set out to write direct, emotionally communicative music in a short span – about 45 minutes – and feature an all-female cast.

Her libretto draws on workshops she held with students from Tipton Academy and Newman University in Birmingham, whose backgrounds added contexts that include FGM and the possibility of "honour" killings. "I asked them: what would you do?" Wallen says. "If you were in that situation, what would happen?" Among her further interviewees were three sex workers from the Birmingham area – all of whom, it turned out, had been drawn into prostitution by older men when desperate for money to fund drug addiction.

Responses from the young audiences to the first performances of Anon in the spring were encouraging, Wallen says. "Girls who had never seen an opera before were coming up to me to ask how they could be involved, saying that every young person should see it," she says. "They wanted to tell their own stories."

'Anon' by Errollyn Wallen, Tête à Tête Opera Festival, Central St Martins Platform Theatre, London N1 (020 7514 8381) 26 & 27 July