This Hitchcock-directed adaptation of the popular adventure novel (reviewed here) retains some plot elements and the basic idea of a hero (Robert Donat) pursued from London to Scotland and back by the police and foreign spies, but it’s otherwise quite different and adds a new major character, an intelligent and self-possessed heroine (Madeleine Carroll), which I thought a major improvement. It had a relatively high budget for a British film of the time, since the studio was hoping it would be successful in the American market as well as at home, and it was.
Some later scenes involving Carroll are slightly naughty for 1935, but Hitchcock knew the censor, who was blind in one eye, and sat on his good side during the screening so he could say things at key moments in order to get the official to look away from the screen.
Besides suspense, mystery, and romance, there’s a good deal of humor and some serious material as well, notably a brief but poignant look into the unhappy marriage of a Scottish woman who helps the hero.
The film has a dated feel, but I enjoyed it. A high point is the scene at a political meeting in which the hero, mistaken for someone else, is forced to extemporize a speech despite having no idea which side his audience is on, and what he says is so brilliantly generic it earns thunderous applause.
Here's a trailer from Criterion's DVD release: