"Mum, I'm going to wet myself" was the cry from a little boy a few rows back on Saturday afternoon. The indulgent family audience chuckled understandingly.

But, honestly, it might have been an elderly critic piping up. For Big Bad Book is leg-crossingly hilarious for punters of all ages. And it also has a moral to please the adults.

Lauren Child's modern children's book, complete with animated illustrations, is brilliantly brought to life in this Soho Theatre production.

Herb (Jeremy Legat) is a boy who finds himself inside a book of fairy stories he's been happily defacing. He meets a Goldilocks with Bonnie Langford Syndrome (a terrific turn by Helen Goldwyn) and a whole assortment of other characters, many courtesy of Sidney Smith (his Fairy Godmother is a show-stealer).

Fifty fun-packed and technically clever minutes for younger children and sly enough to keep the grownups beaming.

But as if having one great Christmas family show wasn't enough, the backroom brains at Warwick have covered themselves in glory by giving us two.

The main hall attraction, aimed at an older audience, is simply stunning. Jason ticks all the seasonal entertainment boxes - slapstick laughs, cross-dressing drollery, scary thrills, a few tears, kids up on stage, singalongs and all the rest.

But there's so much more. The beggarsbelief production plays with audience participation at a much deeper level.

Watchers are expected to have no trouble visualising a few pub picnic tables as a great Greek ship. That very act of imagination becomes part of the dynamic of the narrative as it sails along. So a couple of galvanised bath tubs double as the clashing rocks, for instance.

The really clever and literally spellbinding concept is to have all the drama, the love, the thrills, the heroism, the comradeship and so on grounded in the Ealing comedy antics of an English village fete with its overtones of ancient rituals and magic in the folk dancing and the social hierarchy of rural life.

At a stroke the audience is plunged into what amounts to a dream sequence through which the ancient tale unfolds. Daniel McGowan's excellent Jason, by turns diffident and heroic, is a convincing Everyman , just like us and pulled into great events almost against his will - it's one of an array of brilliant touches throughout the show. It kept our four-year-old transfixed for over two-and-a-half hours - an achievement in itself.

A truly wonderful ensemble cast, great aerial work, terrific music provided by the cast and a wonderful folksy raggle-taggle of props - a terrifying snake made from tin cans, for instance.

An absolute must-see, if only for the Harpies with handbags.

Both shows run at various times and dates until December 31. Check details on 02476524524.

Sid Langley