When Mr and Mrs Clever-Nasty-and-Rich met Mr and Mrs Thick-Sweet-and-Poor

Torben Betts, head boy at Alan Ayckbourn’s unofficial school of apprentices, has written at least a dozen plays I’ve never seen. Invincible, my first encounter with the heir apparent, is a sitcom that pitches London snobs against northern slobs. The script is fascinating because it demonstrates, in concentrated form, the limitations of the Ayckbourn method and the narrowness of his psychological palette. The characters are emanations of tribal prejudices rather than flesh-and-blood human beings.

The plot begins with two earnest Islington prigs moving ‘up north’ after losing money in the recession. Where exactly ‘up north’ is unclear but the accents suggest Blackburn. The pair could win prizes for ghastliness. He’s a stammering emotional eunuch. She’s a hectoring Marxist nightmare. They decide to invite their northern neighbours around for a drink even though they hate northerners, even though the neighbours’ cat has vomited on their herb garden and, yes, even though they don’t drink.