The Grunts in a Jam

The third book in this superlatively silly series sees the gloriously grubby Grunt family head to a country fair so Mrs Grunt's mother can enter her homemade jam in the Preserves, Jams and Jellies Competition. There's nothing in that plan to suggest they'll encounter sabotage, bad poetry and prison, is there? Hmm. This is The Grunts we're talking about...