IT used to be Roald Dahl's stories that always drew children to the theatre, whether The Witches, James And The Giant Peach, The Twits or The BFG.

Now fellow prolific novelist David Walliams is becoming ubiquitous too, ploughing a similar furrow of comedy with an element of the grotesque. First came Gangsta Granny, now Billionaire Boy, and come September, the world premiere of Demon Dentist will be the latest to roll off the Birmingham Stage Company production line (to mark the company's 30th anniversary).

Billionaire Boy is the tale of lonely boy Joe Spud (Matthew Gordon), whose 12th birthday present is a £1 million cheque, just as it was for his 11th birthday. Mum has left Billionaire Dad, Len (Nether Poppleton actor Matthew Mellalieu), whose new billionaire pad is the largest house in Britain, with a butler to boot, having made his fortune from inventing loo roll that is moist on one side, dry on the other.

Joe already has two pet crocodiles, the biggest TV, a simulated Formula One race track, but no friends: a bum deal indeed, especially at his private school, where he is picked on as the "Bottom Billionaire".

Will moving to a new school, the local comp Ruffington High School, change all that in director Neal Foster's boisterous adaptation, where the bum meets the Brum, with the accent on bold caricature performances on a set design made out ofyou guessed it, loo rolls?

There are shades of Molesworth, Adrian Mole and Just William (Just Walliams?!) here, capturing the school world of bullying (the Grubs), teasing, trying to fit in, dealing with petty disciplinarian teachers and trying to avoid the ghastly lunch menu of dinner lady Mrs Trafe (one of several outstanding cameos by Emma Matthews).

Gordon's Joe has a lugubrious air, fed by his Dad's brash ways constantly bringing him further difficulties, especially with fellow outsider Bob (Jake Lomas). Father has even more to learn than son.

Suitable for age five upwards, Billionaire Boy is high spirited, fun at times too, typified by Tuhin Chisti's shopkeeper Raj, but somehow not as fun or as engaging as it could be, not least Jak Poore's underwhelming songs. All in all, that makes it a bit of a bummer.

Performances: 7pm tonight (FRIDAY); 2.30pm, 7pm, Saturday; 11am, 3pm, Sunday. Box office: Box office: 0844 871 7615 or atgtickets.com/York

By Charles Hutchinson