Both of these short novels are illustrated stories aimed at eight and nine-year-olds. Both are playful narratives that tease and tantalise. The similarities end there. Where one book trips along with never a false step, the other plods and founders. One is execrably awful, the other exceedingly good.

Down With The Dirty Danes is narrated by a semi-literate boy. Some words defeat him entirely. “Hees a bit of a passi passyfist pasi he dosent like being hit.” In a madcap, giggle-a-page story told in letters, King Alfred arrives (unrecognised) to do some babysitting and give another account ofhow the cakes were burned.

Roddy Doyle, who writes adult novels successfully, believes a story about stepping in dog poo should appeal to juvenile minds - as well it might. The central idea (that there are small creatures called gigglers ready to dish the dirt on adults who are mean or dishonest to children, by arranging for them to tread on dog mess) is reasonably good and the main character has a Dahl-like charm.

But Doyle squanders his material by indulging in unamusing discursions, such as a tedious running joke about chapter titles. And in a short, expensive hardback, too many chapters are archly throwaway. A disappointment.

Michael Thorn is deputy head of Hawkes Farm primary school, Hailsham, East Sussex