Robert Morley demanded a fee of fifteen thousand pounds sterling when offered the part of Sir Lancelot Spratt. As this would have constituted nearly one-sixth of this movie's proposed budget, the filmmakers instead hired James Robertson Justice at one-tenth the salary. Justice scored a great personal triumph in this movie, and played the role again in five sequels. It was to remain his best-known movie part.
The most popular movie of its year at the U.K. box-office.
In between takes, Kenneth More, Donald Sinden and Donald Houston would interact with each other on the set. By contrast, Dirk Bogarde kept pretty much to himself.
Comedian Tommy Cooper was in one scene, but it was cut from the finished film.
The medical school in this movie was the old St. George's Hospital Medical School, which used to be on Hyde Park Corner (now a plush hotel). St. George's was later moved to Tooting, in southwest London, England.