Owen Jones’s first book, “Chavs: The Demonization of the Working Class,” begins more like a Noël Coward play or a late-model Ian McEwan novel than like a rumbling social polemic. That is, it opens with a misfired witticism uttered at an elite East London dinner party.

Here’s how Mr. Jones sets the scene. “Sitting around the table were people from more than one ethnic group. The gender split was 50-50, and not everyone was straight. All would have placed themselves somewhere left of center politically.” Each guest “would have bristled at being labeled a snob.” Disaster arrived, as it always seems to, with the black currant cheesecake. That’s when the talk turned to the economic crisis. One of the party’s hosts joked: “It’s sad that Woolworth’s is closing. Where will all the chavs buy their Christmas presents?” The other guests tittered. Mr. Jones stewed.

The word chav, if your subscriptions to British periodicals have lapsed, is a noun that essentially means “ugly prole”: loutish, tacky, probably drunken and possibly violent. The stereotypical chav is a hormonal 20-something lad in an Adidas tracksuit, sideways Burberry baseball cap and bling, but women can be chavs, too. Think of Snooki with a cockney accent.

What angered Mr. Jones about the dinner party comment, he explains, is that the joke could easily have been rephrased thus: “It’s sad that Woolworth’s is closing. Where will the ghastly lower classes buy their Christmas presents?” This got him thinking. “How has hatred of working-class people become so socially acceptable?” he asks.