Meet the Lambchops, an all-American family: Mom, perpetually in a pinnie, who cooks delicious breakfast eggs; Dad, breadwinner and disciplinarian; and their two sons, Stanley and Arthur. They are apple-pie perfect until disaster strikes: the message board hung over Stanley’s bed falls from the wall and squishes him flat. He is, by his parents’ reckoning, “four feet tall, about a foot wide and half an inch thick”, and life in this everyday suburban household becomes anything but ordinary.

Jeff Brown’s 1964 children’s book, adapted by Mike Kenny, is brought to the stage in Gail McIntyre’s West Yorkshire Playhouse and Polka co-production with a winning blend of kitsch, cosiness and grotesquerie.

Karen Tennent’s magnetic aquamarine set, to which props are adroitly attached, is both a squeaky-clean Sixties home and a giant version of Stanley’s hazardous messageboard. Our hero and his mother sport Day-Glo tangerine hair and, after the accident, Stanley is represented by a life-sized puppet attached to the feet of his flesh-and-blood double, the actor Stewart Cairns. The new slimline Stanley has legs like two strands of linguine; his head is a disgruntled freckle-faced disc.

Still, being flat has its advantages. An expensive visit to Stanley’s friend in California becomes instantly affordable when Mr and Mrs Lambchop realise they can simply send him through the mail. It’s exhilarating, too, turning himself into a human kite. But it’s not easy being different and soon Stanley longs to be a normal boy again.

If you were feeling earnest, you might interpret the tale as an allegory about rites of passage and the tension between individuality and fitting in. There’s certainly a cautionary subtext that warns of how parents can become preoccupied with one child’s problems at the expense of his or her sibling — in this case, the hurt and resentful Arthur. On the other hand, if, like the show’s target audience, you were aged 3 to 7, you might find the moments when these issues take prominence — as well as an incident in which Stanley foils an art thief — fidget-inducing. But the agile four-strong cast have bags of charm, and the story as a whole is so beguiling, and so refreshingly cynicism-free, that ultimately, like one of Mrs Lambchop’s perfect fried eggs, it lands neatly sunny-side up.

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