Where does a composer get his ideas? “In the most inconvenient places,” says Jonathan Dove. “When I was writing the incidental music for a Pirandello play at the Almeida, a tune came into my head while I was walking through the Brompton Cemetery on the way to a rehearsal. I thought, ‘That’s a strong theme; of course I’ll remember it.’ But after the rehearsal, it had gone. That evening it came back to me – in a restaurant, when I had no paper. I grabbed a napkin and jotted it down. The waiters were very good. They let me go home with it.”

Dove was a late starter. London born and bred, he began his career as a rehearsal pianist (“then I realised my left-hand trills weren’t up to it”) and hardly composed anything substantial before he was 30. He’s certainly made up for it in the past 15 years. Musical notes seem to stream out of him like water from a fountain.

If an opera company wants Wagner’s entire Ring Cycle reorchestrated, as Birmingham Opera Company did a few years ago, Dove is their man. If a town wants a community opera – embracing everything from pensioners’ choirs, brass bands and African dancers to Turkish lute bands and school gamelan ensembles – Dove will pull it together with a resourcefulness and imagination that borders on genius.

If the BBC or Channel 4 wants a snappy, provocative TV opera about, say, the death of Diana, Princess of Wales, Dove will do it with just the right degree of irony and tunefulness. And if the National Theatre wants two hours of atmospheric music to help audiences through a six-hour production of Philip Pullman’s His Dark Materials, it’s the seemingly inexhaustible Dove – bent over his piano in his Hackney bedsit – who will be asked to pick up his lightning quill.

“Actually, I wouldn’t say I was that quick,” he says. “Rossini, Mozart or Handel would have been thoroughly embarrassed to have spent almost a year writing an opera, as I’ve just done. I waste months throwing away bad ideas. But I suppose that, yes, once I’ve worked out what I want to write, I write it relatively fast.”

The opera to which he refers is The Adventures of Pinocchio, which is Opera North’s Christmas show in Leeds. Of course, Dove is being mildly disingenuous when he says that he’s spent a year writing it. In the past 18 months or so he’s also penned a TV opera for Channel 4, a music-theatre piece for the Young Vic ( The Enchanted Pig), and another opera for a Dutch company (anadaptation of Arthur Japin’s novel The Two Hearts of Kwasi Beach).

But Pinocchio is different. For a start, it’s a vast and spectacular undertaking: no fewer than 27 named characters, plus chorus and orchestra. Second, it’s a story that we all know, or think we know. That means we bring a baggage of expectations into the theatre.

And third, it’s that rare thing: an opera conceived for all the family. “It was important to write something that would appeal to parents, older children and younger children as well,” Dove says. “The opera world isn’t too well supplied with pieces like that. After Hansel and Gretel and The Magic Flute, what is there?”

But any notion that Pinocchio will be a cosy, condescending entertainment can be dispelled. “I wouldn’t mind if younger children found our treatment a bit frightening sometimes,” Dove says. “Children like to be frightened.”

Dove and his librettist, Alasdair Middleton, have mostly shut their eyes and ears to the saccharine allure of Walt Disney’s film, and returned to both the spirit and the plot of Carlo Collodi’s original 1883 book.

“The book has many more events in it than the film, and it's a darker, stranger story,” Dove says. “For instance in Disney the cricket is a major figure, and appears all the way through – as the voice of Pinocchio’s conscience, if you like. But in the book, when the cricket appears Pinocchio almost immediately squashes him with a mallet. So much for the voice of conscience! Of course, such is the nature of this surreal story that the cricket is back from the dead at the end – no explanation!”

Dove also claims that Pinocchio himself, who’s a bit of a goofy simpleton in Disney’s hands, undergoes a far stronger, more dramatic transformation in the original story. “What’s exciting is that he starts as this wilful, impetuous, self-centred being, incapable of delaying gratification of an impulse, always making promises that he will do the right thing, and immediately breaking them. But then he hits rock bottom, is left for dead several times, and undergoes a kind of rebirth. There’s a turning-point in the story. For the first time we see Pinocchio do something to help someone else – he gives away the money he has earned to help the Snail get better. And that’s the point in which he turns into a real human being.” Dove relishes the vocal opportunities that such an episodic story provides. “I have a deep bass for all the scary men. There’s a coloratura soprano to be the cricket. The Blue Fairy is a soprano, Mary Plazas. And Pinocchio is a mezzo, Victoria Simmonds. Bizarrely, Pinocchio was the first role that Vicky ever played on the stage – at the age of 10!”

And the music? Dove is renowned for his chameleon-like ability to evoke different musical genres in order to heighten the drama or delineate a character. Will that be the case here? “Well, any composer writing something about a puppet is bound to feel the shadow of Stravinsky’s Petrushka,” Dove replies. “But the piece has a lot of strongly contrasted types of music. My attitude was that if I wrote something that I would find entertaining, there’s a chance that other people will, too.”

And what’s next for the prolific Dove? Three more operas before breakfast? “I’m taking six months off. I’m going to read lots of books that have nothing to do with music.”

Pinocchio, Grand Theatre, Leeds (www.operanorth.co.uk 0113-222 6222), Dec 21-29, and then on tour

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