Doctor in Distress (1963)

"Doctor in Distress" is the fifth of the seven films in the "Doctor" series, and focuses on Sir Lancelot Spratt, Simon Sparrow's old teacher and sometimes nemesis. When the eternal bachelor Sir Lancelot injures his back and falls in love with his physiotherapist Iris Marchant, he becomes very distressed and turns to Simon for help. Simon, who now is a senior doctor at fictional Hampden Cross Hospital and hopelessly in love with aspiring actress Delia, sends him to a nature cure clinic in a vain attempt to help him lose weight, but Sir Lancelot can't get Iris off his mind and has her followed, first by a private investigator and eventually by himself. When he finally proposes, she rejects him and marries an old army major, which distresses Sir Lancelot even more.

Comedy