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.
This movie was made on a budget of just ninety-seven thousand pounds sterling. Producer Betty Box claimed that it got back almost its entire cost during its initial run at one cinema in London's West End.
The four medical students were all played by actors in their thirties. Kenneth More, who is actually supposed to be older, was almost 40. In fact he was older than Geoffrey Keen who played the Dean of the medical college.
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.