Factual error: One of the operetta excerpts shown in the movie is the humorous song "This Helmet I Suppose," during which Princess Ida's three brothers are supposed to remove their armor piece by piece, finding it heavy, hot and awkward. Partly as a result of this, the three are soon afterwards quickly and easily defeated in combat. In the film, however, only Arac, the brother singing the verses (played by Richard Temple (played by Timothy Spall)), removes his armor. The others simply stand still. (This might have made the battle scene end differently if it was shown on screen!)

Factual error: When the choristers are discussing whether to complain to Gilbert about his omission of Richard Temple's solo, one male singer refuses, saying that he has been with Carte's company for 38 seasons. However, the company had only been in existence for seven years in 1885.

Factual error: This film deals with the events leading up to and including the creation and original production of Gilbert and Sullivan's operetta "The Mikado." The performance of the trio "Three Little Maids From School" includes a bassoon solo (occurring twice after the words "freed from its genius tutelary") that was not actually added until years later. However, performing the piece in a form other than its definitive and improved version would certainly be carrying authenticity too far.

Factual error: When Gilbert's rehearsal accompanist Mrs. Russell, who is bilingual in Italian and English, becomes exasperated, she says, "Ma non posso lavoro così." ("But I can't work like this.") This should be "Ma non posso lavorare così." ("Lavoro" would be either the first person singular of the present tense indicative ("I work") or the noun "work.") Her accent is spot on, however.

Deliberate "mistake": The song "If you give me your attention" (from "Princess Ida") and the Mikado's song (from "The Mikado," of course) are performed with their central verses omitted. This was no doubt to save time and, in the case of the Mikado's song, to avoid inclusion of the line "is blacked like a ni**er" (altered in 1948 to "is painted with vigour").