The Frost Report (BBC, 1966-67):
John Cleese, Ronnie Barker,
Ronnie Corbett

Britain's ancient class system has always been a mystery to foreigners, and a source of endless fascination - and humour - to the British.

In the past, the British were expected to 'know their place'. That is, to accept their status as working-class, middle-class or upper-class and to behave in a manner appropriate to that status. Those who tried to pass themselves off as a member of a higher social class - to 'put on airs' - were frowned upon or, often, laughed at.

In the hugely successful 1960s sitcom Steptoe and Son, 'rag and bone man' Harold Steptoe is forever seeking escape from his poverty and lowly status. But his ambitions are always frustrated, usually by his scheming, needy father, Albert. Although audiences sympathised with Harold, they couldn't help laughing at his hopeless dreaming.

Whatever Happened to the Likely Lads deals with two Newcastle-born friends who have chosen different paths. The humour derives from the ambitious Bob's attempts to reconcile two competing needs - his longing for a middle-class, 'respectable' life, as represented by his executive job and his new wife Thelma, and his wish to stay true to his working-class roots, represented by lifelong friend Terry, who makes endless fun of Bob's aspirations.

Much of the comedy of Dad's Army was at the expense of bank manager Captain Mainwaring, whose petit-bourgeois authoritarianism contrasted sharply with the relaxed approach of the urbane, aristocratic Sergeant Wilson.

The Good Life mocked 1970s' middle-class lifestyles in its story of a middle-aged couple, Tom and Barbara, who shock conservative Surbiton, and particularly their snobbish neighbours Margot and Jerry, by exchanging comfortable conformity for a self-sufficient life, filling their garden with home-grown fruit, vegetables and even a pig.

In Keeping Up Appearances, status-obsessed Hyacinth Bucket (pronounced, she insists, 'Bouquet'), goes to desperate lengths to impress her neighbours of her class and good breeding but, inevitably, her efforts are undermined by her embarrassing, slobby relatives.

Sketch shows, too, have often highlighted the absurdities of Britain's class system. Famous examples include several Monty Python sketches and a 1960s routine featuring John Cleese, Ronnie Barker and Ronnie Corbett from The Frost Report.