Hans Christian Andersen’s ugly duckling didn’t have a particularly nice time before he discovered that he belonged to a grander species, but his sufferings were nothing compared to those endured by Philip Osment’s titular bird. Even his comfy old auntie, who was born at Highgrove and thinks it beneath her to have a scraggy-looking nephew, suggests to his mum that she feed him to the foxes. And the poor young chap duly encounters one who amiably offers to rid him of his suicidal feelings by ripping open his throat, eating him and giving his eyes to the crows.

Though I would not recommend the play to the very young or squeamish, it should restore the juices of children who have feasted too much on Snow White or other Christmas sweetmeats. Yes, Osment is more obviously didactic than Andersen when it comes to preaching the virtues of tolerance, exposing bullies, discussing problems of identity or interesting the young in ecology. But he is refreshingly tough-minded and, thanks also to Rosamunde Hutt’s production, tells a gripping, pacy story which, when I saw it, kept an audience, aged 7 to 12, totally absorbed.

The scene is a “heath”, presumably Hampstead, where Inika Leigh Wright’s frilly Mother Duck starts off perched on an egg the size and shape of the “gherkin” in London. Out totters Liam Lane’s Ugly to general horror: which is odd because one of a deftly imaginative production’s few faults is to distinguish insufficiently between looks and costumes. Nevertheless, his yellow-capped, yellow-booted brothers are soon joining the rest of the pond life in tormenting a creature whose crime is to look a bit taller and rather whiter.

With coots pecking and insulting him, a social worker heron blaming him for the trouble he causes, a headmaster mallard attacking him for eating snails and saying “honk” instead of “quack”, it is no wonder Ugly flees the pond. But out there he finds a menacing pitbull whose owner shoots one of the Canada geese rappers who have befriended him, and a crow who urges the poor, despairing cygnet to lie in the snow and turn into carrion. From time to time the cast also transmutes into humans, most of them kinder.

One, weirdly and gratuitously, is the ghost of Boadicea who delivers a homily on bullying to a chastened fox. Another is an Irish tramp who talks about the logic of nature and the wisdom of creation. Others are children who briefly take home the freezing bird and provide a parallel to his predicament. Their father has, it seems, deserted the family for another man – and his distressed son has to accept that some people, like some birds, are different.

I suspect that the inference that closeted gays may be swans in disguise went over the heads of most of the kids. In any case, such preachiness is forgotten when Ugly and his new-found chums take to the skies to the strains of Tchaikovsky. After all the agonising, Osment’s Swan Pond has a happy ending.

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