Apart from Humperdinck’s Hansel and Gretel, few operas written with children as the target audience have established a foothold in the standard repertoire. So Jonathan Dove’s new magnum opus, The Adventures of Pinocchio, closely based on Carlo Collodi’s fable, is a welcome addition to the bill of seasonal operatic fare.

It is a big piece in every sense: it consists of two acts of Wagnerian length (75 minutes each) and requires the substantial musical forces of a medium-scale opera company, 25 solo parts (many of them short and doubled), orchestra and chorus.

In this respect, it is very much an adult opera, too, like Humper-dinck’s masterpiece: a children’s opera with dark undertones. Alasdair Middleton’s libretto follows the often sinister original tale as Geppetto’s marionette “child” is transformed from a block of wood – the opening scene depicts a log in the forest that sings “Make me!” to the old man – and eventually, after picaresque adventures, becomes a real boy.

Characteristically, Dove and Middleton have made a point of deDisneying the famous story: Jiminy Cricket – Pinocchio’s companion and the voice of his conscience in the cartoon film – reverts to Collodi’s Cricket and is quickly dispatched with a mallet, returning only once, as a ghost, to underline Pinocchio’s development into a human being. (The cricket’s ghost is a manifestation of the wooden boy’s feelings of guilt at killing him.)

Inevitably, reverting to Collodi’s action-packed narrative has a down-side. In a programme interview, Middleton reveals that the model for his libretto was Colette’s famously pithy book for Ravel’s L’Enfant et les sortilèges (The Child and the Magic Apparitions), but, no doubt encouraged by Dove, he provides enough scenes for three operas. I couldn’t help feeling that Dove and Middleton’s Pinocchio could have profited from some of Ravel and Colette’s terseness. Their no less action-packed opera lasts a mere 45 minutes, without a wasted word or note; this Pinocchio inevitably drags when Dove seems to rely too heavily on his facility for note-spinning, rather than real inspiration. Far too many of the episodes seem like padding and, for all the beauty of Dove’s melodic lines, and his often exquisite orchestration, his “minimalist” idiom can’t sustain interest over such long acts. This is the weakness of so much repetitive music. For “repetitive”, read lack of ideas.

Certainly, Dove takes great pains to bring colouristic variety to his score – his glittering, spangly music for the Blue Fairy scenes and the pulsing energy of his big theatrical set pieces strike me as his most signal successes – but the theatrical momentum sags under the weight of too many scene changes and characters.

Even so, Opera North has done Dove, Middleton and Collodi proud with its magical staging by Martin Duncan, who makes the narrative as clear as possible and, helped by Francis O’Connor’s fantastical set and costume designs, provides visual treats aplenty. O’Connor’s basic set is a wooden interior hung with woodcutters’ tools and implements: huge saws and hatchets that lend a sinister framework to the action. Duncan and O’Connor are masters of transformation, however, and the 20 scene changes are deftly handled: most spectacular of all is the penultimate episode, Inside the Big Fish, in which Pinocchio and Geppetto are reunited. The stage of Leeds’s Grand Theatre teems with life in the big public scenes. The appearance of the Big Green Fisherman – a giant puppet manipulated by three men – was a coup de théâtre that provoked a frisson of awe.

Under the evangelical baton of David Parry, a dedicated Doveite, the musical performance is as fine as one would expect from Opera North; and, as always with this company, ensemble values are paramount in the casting. The one star part, of course, is Pinocchio, a mezzo-travesty role in the tradition of Mozart’s Cherubino or Humper-dinck’s Hansel. He is wonderfully played and sung by Victoria Simmonds. The make-up and props department deserve special mention for their work in transforming Simmonds into a wooden boy with a very long nose. The veteran Jonathan Summers is ideal as the bumbling, warm-hearted Geppetto, while Mary Plazas brings special vocal allure and charisma to the Blue Fairy’s appearances. Among the excellent supporting cast, Rebecca Bottone’s bright color-atura soprano stood out in the roles of the Cricket and a Parrot, Mark Wilde and James Laing were a Laurel and Hardyesque double act as the Cat and Fox, Graeme Broad-bent snarled darkly as the Fire-Eater, Ape-Judge and Big Green Fisherman, and Carol Wilson again showed her skills as a character actress with her Amy Johnson-like Pigeon and bag-lady Snail.

Despite occasional longueurs – I hope that Dove will have the courage to shorten it for future revivals – The Adventures of Pinocchio has enough old-fashioned theatrical magic, and sufficient musical thrills and spills, to find favour with audiences young and old, as it tours the land from the end of the month.