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The creators may claim as much, but...

Lexicographer Tony Thorne, in his 1990 Dictionary of Contemporary Slang (ISBN 0-7475-2856-X), reports instances of "smeg" (and derivatives) being used as a term of "mild contempt and even affection" among "schoolboys, students and punks" as early as the mid-1970s — a decade or so prior to the inception of the Red Dwarf phenomenon — and claims unequivocally that the etymology of the term traces back to "smegma".