For anyone under the age of, ooh ... 43, attending a classical music concert can be a disheartening experience. The tutting retirees; the impenetrable programme notes; the vexed issue of when you're allowed to clap. If you've bought tickets to hear some great music, why does it have to be such hard work?

One person who may have the answer is Suzi Digby, the internationally renowned choral director and conductor, who now hopes to bring classical music back from the brink. With her innovative new scheme, Vocal Futures, she hopes to prove that youngsters from any background can form a lifelong relationship with classical music.

A glamorous and assertive 53-year-old (the wife of Labour peer Lord Eatwell), Digby has spent the best part of her career travelling the world, identifying the barriers to young people enjoying classical music.

"Every other genre is moving forward, whether jazz or R&B. But classical music is just, well, ugh!" she laughs. "Kids are used to the high production values of Lady Gaga. You can't fob them off!"

Her first project has brought together 300 socially and ethnically diverse young Londoners between 16 and 22 to attend one of three staged performances of Bach's St Matthew Passion (tonight's is the final performance). As well as witnessing the story of Jesus's trial, crucifixion and burial, they have also sung the last chorale of the Passion. Their pre-recorded four-part harmony performance has been edited together for a video which is broadcast at the climax of the show, alongside live performances from professionals including Jamaican opera star Sir Willard White.

The concerts are staged at Ambika P3, a concrete bunker in Marylebone that has been transformed by director and designer Patrick Kinmonth using actors, singers, The Orchestra of the Age of Enlightenment and a specially built set.

And the young people or "ambassadors", whose role is to spread the word about classical music, have been recruited from 10 pre-existing "hub" organisations, ranging from city academy schools to youth agencies. While they all have an interest in music, many will never have attended a classical concert. "Whether it's the inner-city Muslim community or Cambridge undergraduates, common to that age demographic is the fall-off in attendance at classical music concerts," says Digby.

Her approach of working through local community "hubs" has been echoed in government plans announced this week for music education. As part of the first national scheme for music, inspired by the much-lauded Venezuelan El Sistema scheme, all children between the ages of five and 18 will now be offered intensive instrumental training for at least one school term. Like Digby, the Government has recognised that music tuition needs to be made available and affordable to all young people.

For the past two months, Digby's group has been in training to appreciate Bach's intricate Baroque music. Group workshops with musicians and production staff have immersed them in the story of Christ's crucifixion. The youngsters have also studied the vocal and instrumental demands of the music, and the technical, design and marketing challenges of staging the production. It's an ambitious and costly programme but Digby says: "I'm not interested in shallow solutions.

These kids need to understand how a production comes together. When you come to grips with one of the greatest artistic achievements of mankind, the potential is for it to be transfigurative."

When the ambassadors met to form a choir, Digby admits she was terrified they would lose interest and walk out. "I thought it was a social experiment that could easily go wrong, but these kids just didn't want to go home. They were asking me what they should listen to next." One young ambassador has commented: "It has made me view classical music differently and I actually find it incredibly beautiful."

In between the workshops and performances, the ambassadors are downloading online resources and comparing notes in chat rooms. The social element is a strong hook, helping them to feel invested in the performances.

The project doesn't end with tonight's performances. For six months after the Passion is staged, researchers and psychologists will examine the young people's attitude towards classical music as a result of being involved with Vocal Futures. The results will be published next summer.

"So far, nobody's really been able to get a purchase on the 16-22 age group, when their character is forming and they're developing their relationship with the world. I am looking for what I call 'the Red Bull wings moment' when their interest soars," says Digby, who sends out daily messages via email, Facebook and Twitter to "chivvy on" the young ambassadors.

This is a very personal mission for Digby. She describes herself as a "Diaghilev-plus personality" (like the great ballet impresario, she has a talent for bringing people together). Her own childhood, coloured by mental illness in her family, taught her "how to reach out to people who didn't feel great about themselves".

Her enthusiasm has enabled her to raise the funds for the project (more than £500,000) all by herself in six months.

"I nearly killed myself. No one believed I could get the money, but I broke the Passion up into 50 chunks and I sold each for £5,000. Stephen Fry bought a chorus, and various people have bought arias. It's no different from selling a Chanel handbag - it's an investment piece."

Fry, who has been a vocal supporter of the project, believes that when young people say they find classical music boring, they don't really mean that. "People use the word 'boring' as a defence mechanism about anything they don't like because they are afraid of it, afraid of embarking on a journey that may ... require an emotional investment. It's easier to say 'no'." But you sense that people rarely say no to Digby.

She believes that Vocal Futures is a prototype that can be scaled up for other arts organisations who too often approach education projects as a secondary concern. "Many only do education because it means they get a grant. That's just thinking about education backwards," she says. By next year, she intends for the project to go to Shanghai, Cologne, Los Angeles and Johannesburg.

And once it's gone global? Her next project with Vocal Futures will be Beethoven's ninth staged in a "vertical auditorium". What's a vertical auditorium, I ask? She raises her eyes up, skywards and gestures towards the impossible.

Bach's St Matthew Passion is at Ambika P3, NW3, tonight (vocal futures.org, 020 7638 8891).