Facebook is apparently developing technology that determines users’ social class. But I don’t know why they bothered. You can immediately judge anyone’s class on the basis of how they refer to their grandmothers. If you call her “nan” or “nanna” you’re almost certainly working class. If you call her “grandma” or “granny” you’re probably middle class. And if you call her “the Dowager Duchess of Chorlton-cum-Hardy” you’re proper posh and there’s no mistake, missus.