I never quite twigged why a sane-seeming father would take his children through river, forest, mud and a snowstorm to catch a bear, still less why they should bring with them little but a butterfly net, a magnifying glass and a dog that doubles as a guitarist. But the tots around me clearly had no difficulty buying the idea behind this adaptation of Michael Rosen’s book, so nor should I. Nor should you if you decide to take yourself and your brood to this likeable if unremarkable holiday diversion.

Few would quarrel with the director, Sally Cookson, when she writes in the programme that children’s “ability to enter an imaginary world instantly without inhibition or cynicism fascinates and delights me”. All she needs for that river are blue plastic buckets in which the characters splash before spraying their audience with water. Rather less entertainingly, the forest is a lot of cardboard boxes and the snowstorm a white sheet. “We can’t go over it, we can’t go under it, we’ve got to go through it,” they repeat before each obstacle, getting the spectators to chorus the same words with them.

Small children love repetititions such as that or the show’s other mantra: “What a beautiful day, we’re not scared.” They also enjoy a modest dollop of scariness, which is what they get here. Every so often there’s a growl from offstage. But when, if ever, will a grizzly appear? Into a pretend cave the weird little family goes and declares it can see “two big furry ears, two big goggly eyes and one big wet nose”. But the bear that then materialises isn’t anything like the one that scares, tears and devours Antigonus in the current revival of The Winter’s Tale at at the Old Vic. It’s a giant teddy, which does a happy little dance.

Again, I couldn’t quite understand why the teddy seems also to contain Duncan Foster’s Dad, but, again, the children around me were unsurprised. Maybe they came from homes where fathers take refuge from the world’s pressures by hiding inside furry animals. Come to think of it, that’s a wiser option than asking their children to chase bears.

Box office:0844 4124659 to August 16

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