Perhaps orchestras should be keener to advertise their world premieres as being suitable for children: it’s not often that new orchestral music gets an audience as packed and attentive as this one, even – or perhaps especially – for such a heavyweight composer as Colin Matthews.

Commissioned by the London Philharmonic in tandem with orchestras in Sydney and Seattle, and premiered on a Sunday lunchtime as an upbeat opener to the Southbank Centre’s Imagine children’s festival, Matthews’s new 50-minute score does not talk down to the youngest in its audience – something in which he emulates his mentor Benjamin Britten.

The text is from Michael Morpurgo’s book, a retelling of the Pied Piper story that makes the sinister fairytale into an ultimately uplifting fable about social responsibility. Natalie Walter and Morpurgo himself were the narrators, Vladimir Jurowski the conductor; behind the orchestra and the excellent choir of Deansfield primary school were projected Emma Chichester Clark’s quietly evocative illustrations from the book.

The music is more than illustrative. The Piper’s instrument of enchantment is a flute, and Matthews uses a quote from Debussy’s famous flute solo Syrinx as a kind of touchstone. It leads off at the beginning, then emerges from the orchestra at the moment of rat-charming, sounding beguiling over muted strings and harp. The music that charms the children away, however, is a wistful jig. The door opens to reveal the Piper for the first time with a grand, fateful theme that returns, with greater menace, when the hillside opens up.

The choir could perhaps have been given more to do, and the passage when the town is rebuilt seems more static than the rest – but otherwise, the piece is beautifully judged, and the LPO did it full justice. If Matthews really does want to write a children’s opera, as he suggested in the programme, he should get Morpurgo on board and start today.