If illustrated children's books present a design problem when translated to the stage, television cartoons and animations offer an even bigger one. You could tell that designers Russell Dean and Simon Scullion had worked out just how to do it from the total commitment of the very young audience to Richard Lewis' adaptation of Ben and Holly's Little Kingdom.

Dean's masks are a triumph – they look good and the actors are at ease wearing them; the costumes also have just the right bright blend of stylisation and practicality. Scullion's perambulating sets are properly cartoonish, and there's a good use of oriental theatre techniques, which the children took at face value, whether the hard-working black-masked stage managers wielding rod puppets, or undulating swatches of silk for Lucy's bedclothes and the jelly tide.

Danielle Black is the girl inadvertently woken by Nicky Cross' Nanny Plum in her tooth fairy guise. We meet her first as a larger than life size face, then she shrinks to join Kerry Gooderson's Holly and Nicola Hart's Ben in their fairy kingdom. Mayhem ensues with Nanny Plum always getting her spells wrong and Ben blowing his horn at inopportune moments. But, with the aid of a hefty dose of audience participation, a ladybird called Gaston who barks, a slug, a spider and a burping frog (very popular), King Thistle (David Sandham) has a birthday to remember.

Subtly included are some messages about saying "please" and "thank you", respecting other people or species and being prepared to own up when you've made a mistake. There's a catchy score by Mani Svavarsson as well as a couple of familiar sing-along tunes. Overall, it's good value for money as far as parents and other senior ticket-buyers are concerned – and a very good introduction to the magic of theatre for small children.