It was on this day in 1898 that frequent supporting actor Oskar Homolka was born in Vienna. (Being of Germanic descent, his given name was originally spelled with a K, although when he started working in British cinema and Hollywood, he got credit in a lot of his movies as "Oscar" Homolka, which is a joy for modern internet image searches.) He made several movies in German before going to England in the mid 1930s; however, it's one of those early British movies that I'm going to recommend: Sabotage.
Sylvia Sidney stars as an American woman who's moved with her kid brother to England to raise him, and is married to Homolka; together they're running a London movie theater and living in the apartment behind it. What Sidney doesn't realize is that her husband is actually an agent of a foreign country, involved in committing acts of sabotage. Don't worry; I'm not giving anything in the plot away by pointing this out. Hitchcock reveals right in the first few minutes that Homolka is an agent and has committed the sabotage. Added to the mix is the greengrocer's assistant in the shop next door (John Loder); he seems to have his eye on Sidney, although we quickly learn that he has other reasons for taking such an interest in the young lady and her brother.
Matters come to a head when Homolka gets his next assignment, involving a bomb. Unfortunately, by this time he's learned that the police are on to him (although his wife, who is completely innocent, still has to figure it out). He can't leave the house, since the police will nab him, and decides to use the kid brother as an unwitting courier, which leads to the climactic chain of events....
Hitchcock had problems with Sabotage, in that he regretted some of the decisions he made regarding the plot. I won't reveal those decisions, since it would give away more important plot details than should be mentioned, but in looking at the movie through more modern eyes, I think what Hitchcock did actually makes the picture better. (I can, though, understand why 1930s audiences might not have liked it.) The ending is also fascinating in that Sidney and Loder, who it turns out is not really a greengrocer but a Scotland Yard officer (this is revealed maybe a third of the way into the movie) both wind up having some moral ambiguity. On the face of it, it's a happy ending -- the espionage ring appears to be broken up, and Sidney looks like she's going to find love again with Loder. But deeper down, it's much darker.
Sabotage has been released to DVD. Please note as well that this is a completely different movie from Saboteur. (Not that Saboteur isn't a great movie; it's just that you need to make certain you're getting the movie you intend.)