Although Raquel Welch is featured in most of the promotional material for this movie, she is on-screen for only roughly seven minutes.
At the time of its release, blasphemy was considered a common-law offense in the U.K., and the British Board of Film Censors was concerned that this movie's premise would offend religious groups. Stanley Donen defended this movie against such claims. To prove his point, Donen claimed that he screened this movie to a London rector and the Arch Deacon of Westminster Abbey, both of whom took no offense to this movie. After that assurance, the case was dropped. By 2005, standards about what could be considered blasphemous in Britain had been relaxed such that when this movie was resubmitted to what was now called the British Board of Film Classification, the only problem they had was with a particular scene involving Stanley's hanging attempts, which had the potential to be considered a glamorous depiction of suicide. (The solution was raising this movie's previous "PG" rating to a "12".)
An article about Peter Cook that appeared in "The New Yorker" stated that the filmmakers didn't have a title for this movie when it was being made. Cook suggested calling this movie "Raquel Welch". The producers didn't understand why Cook would want to name the movie after an actress who appears in it for only a few minutes. Cook explained that movie marquees put the lead actors names over the movie title. Thus, the letters on the marquee would say "Peter Cook and Dudley Moore in Raquel Welch". The producers ended up going for the more ordinary title.
Dudley Moore adopted the moniker Stanley Moon in this movie after Sir John Gielgud wrote him a letter of introduction because he was impressed with Moore's work in the stage revue "Beyond the Fringe". Gielgud referred to Moore as "Stanley Moon" in the letter, and an amused Moore adopted the name as an alter ego for the rest of his life. After they worked on Arthur (1981) and Arthur 2: Dans la dèche (1988), Gielgud good-naturedly said that he "got to know Stanley Moon rather well."
George Spiggott is always wearing red socks, even when he's a fly.