As the film was being made against the clock in order to beat Oscar Wilde (1960) to cinemas, most scenes had to be filmed in one take. However, after the first take of the scene where the Marquis of Queensberry (Lionel Jeffries) strikes his son, Lord Alfred Douglas (John Fraser), Fraser felt his reaction lacked the required passion. He asked director Ken Hughes for another take, which Hughes agreed to, with some reluctance. As the shot of Fraser's reaction was being set up again, Jeffries asked Fraser if he should hit Fraser for real. After a moment of hesitation, Fraser agreed, and Jeffries smacked him with full force, with Fraser's stunned reaction to the slap perfectly captured on screen.
The producers, Irving Allen and Albert R. Broccoli took a chance and financed the film themselves. The film dealt with Oscar Wilde's homosexuality, so very few theaters would play the film. It almost put the producers to bankruptcy, and broke up the partnership between them, but in Europe it was a great artistic success and won several foreign awards. This also ended Warwick Films - Broccoli's falling out with Allen (which also included optioning the rights to the Ian Fleming's James Bond novels) and resulted in the establishment of Eon Productions where he partnered with Harry Saltzman (who held the option rights) - the result was a successful franchise (James Bond) which has lasted for over 50 years.
The editor, Geoffrey Foot had to work fast on "The Trials of Oscar Wilde (1960)" as another film about Wilde, "Oscar Wilde (1960)," was being made at the same time. At one point, the composer Ron Goodwin was recording music before scenes were filmed. Foot still edited the score flawlessly. From start to finish, the picture was made in nine weeks.
John Gielgud wrote that he was originally offered the role of Wilde, having had major successes directing Wilde's plays "Lady Windemere's Fan" and "The Importance of Being Earnest" (the latter also being one of Gielgud's most famous non-Shakespearean acting roles). He turned the film down, writing "no one could look less like Wilde than I do, not even Peter Finch."
Lionel Jeffries, aged 33 at the time of filming, was only five years older than John Fraser who played his son.