A 1948 document just released as a book by the BBC, Variety Programmes Policy Guide for Writers and Producers, details the vulgarities considered by the Corporation hierarchy to be just too blush-making for their audience.
Jokes about ladies' underwear are forbidden. Thus, say the rules, "winter draws on" is an "unacceptable" joke.
All mimicry needs the permission of the people being impersonated, says the book. A ban on impersonating Winston Churchill is set down, and special permission from the higher echelons is needed to mimic Vera Lynn or Gracie Fields.BBC top brass also ruled that Parliament, its Acts and the constitution must never be referred to in a derogatory way. Jeremy Paxman might have had slim pickings; they banned anything that could be construed as personal criticism of ministers, party leaders or MPs.
The one rule that would offend a modern audience is that which permits the term "nigger minstrels". And perhaps the most ignored rule is the outlawing of jokes that might be taken to encourage "spivs" or "drones" - species that were to pepper sit-coms in the Sixties.
The BBC says the little green book, retailing for pounds 4.99, is intended as a light-hearted commentary on the mores of former times.