At their broadest, and most audience-friendly, sitcoms thrive on stock characters: chancers, jobsworths, slobs and snobs. No actor has ever been more suited to the last than Penelope Keith. Others have played funny snobs, but she was a walking colour chart of snobbery. Her greatest strength was her ability to always locate a new variation on the same theme, picking out any number of tones and nuances to give each of her characters more life than their writers probably anticipated.
The big one, of course, was Margo Leadbetter in The Good Life, which ran from 1975 to 1978. On paper, her role was simply to provide contrast. Richard Briers and Felicity Kendal played the leads, Tom and Barbara, two self-sufficient dreamers in frayed clothes who were never happier than when they had dirt under their fingernails. By design, Keith was meant to represent the opposite; stiffer and more materialistic and appalled by anyone who didn’t follow social convention to the letter.
