Preview: Different Voices, Cadogan Hall, London

Where better to set a children's musical than in a park? Different Voices, to be premiered next Monday by the Royal Philharmonic Orchestra, with Stephen Fry narrating, takes place in a lightly fictionalised Regent's Park. It turns on the tension between those who love the park and the developer who wants to turn it into a supermarket and multistorey car-park.

The film composer Debbie Wiseman hatched this idea (she will conduct, too) in response to an invitation to celebrate the RPO's 60th birthday, when she realised that she could also simultaneously celebrate Britten's The Young Person's Guide to the Orchestra by writing an equivalent piece of didacticism for today.

As she outlines it, her work sounds reminiscent of Peter and the Wolf, with Fry emulating Peter Ustinov. But Wiseman insists her piece will leave more to the imagination, and will make the listener work harder. "I also wanted to make it a warm, encouraging piece for children to play. I want youth orchestras to see it as a possible addition to their repertoire. Every instrument has its moment to shine, so in that way it will be challenging as well."

The builders, she says, will be played by the percussion, while the violin soloist will represent the girl who plays the lead character, with the rest of the strings representing her friends. "The only time you get all the instruments playing in harmony is when the battle to save the park is finally won."

This premiere will also boast a singer - Hayley Westenra. When I question Wiseman as to this crossover star's classical credentials, I get a defiant response: "She has a unique voice, and a rare ability to make the simplest melody sound beautiful." Then she plays me the disc that shot Westenra to fame and fortune, and saved the fortunes of its ailing record company for another year. Now, this young singer must prove herself in a somewhat more testing context.

9 April (020-7730 4500)