Katie Tearle is a determined woman who has been quietly laying the foundations for this project for several years. Its genesis lay in two community operas: an allegorical treatment of Channel tunnel themes that she masterminded in Ashford, at a time when that town seemed destined for a rude upheaval; and an equally allegorical fantasy set partly in Peterborough's cathedral and partly in an adjoining shopping centre. But as Stephen Langridge, director of these productions, points outs, such site-specificness had its drawbacks: they could not be staged anywhere else, or by any other performers.
But Tearle had also been working with librettist Stephen Plaice on a project with the probation service, and she suggested to him that he should develop an opera specifically for young performers. "But we knew from the start that this would work only if we began by workshopping it in schools, and by finding out what they themselves wanted to see on stage.We decided to do it with pupils from schools round Glyndebourne, and to stage it in the opera house, at a time when the building was not otherwise being used."
So Langridge and Plaice went into Sussex classrooms, and listened and learned. "We had completely open minds when we started," says Langridge. "We simply had a vague notion of something along the lines of Lord of the Flies. The idea quickly moved to a more contemporary arena, but we still noticed that
it was when they imagined themselves in a world without adults that the kids' conversation really took fire. That remained the principle that guided us."
"We got them to talk about things which are normally adolescent secrets - like what happens at a sleep-over. How do you get the alcohol for it? How do you get your X-rated films? And what do you do all night? Most of the time they're just sitting around, talking, and getting mildly and pleasurably frightened.
"The other very fruitful area which we got them to imagine for us was the playground. We first asked them to portray a secondary school playground, and then to remember a primary school one - and that was another tinder-moment.
"It was the difference between something open, excited and mixed-sex, and something grim, separated, and with no games except football. They told us that if you carried on playing primary games in secondary school, you got written off as 'sad'. This tension became a key to our opera."
Misper is the title - from the police argot for "missing person"; the plot swings melodramatically between the fictional 20th century town of Crayford and medieval China, between bedrooms and railway tunnels, and it contains playground violence and a train crash.
Alison Chitty, who is taking time off from designing Turandot at the Bastille Opera in Paris, says that it's turning out to be one of the most difficult things she has ever had to stage; her budget may be large in educational terms, but in terms of kosher opera it's painfully small.
She is resorting to tricks with lighting, and re-using anything suitable to hand, but she expects the result to be all the more dramatic. She has been quizzing the actors minutely about how they decorate their bedrooms, and on the complex rules of adolescent sartorial etiquette. "I told them that this was an educational project," she says. "And that the person who needed educating was me."
More than 200 teenagers were auditioned and the cast of 70, including doubles for the three most demanding roles, are now in daily rehearsal.
When I dropped in, they were learning how to wreck a classroom in the most flamboyant manner possible, and how to sing most tenderly. A surprisingly large number told me that they were determined on a life in showbiz, and to hell with the precariousness and penury of it. Many were already veteran school performers.
So a big hand for Misper, when it opens for business on February 27, followed by three shows on the next two days. And a fair wind in its sails,so that - as a free-standing work - it can blow round the country, and be revived by different groups, in different climes.
Further information, plus a teacher's pack, from 01273 815025