Blackmail is both a film important for its place in cinema history and a compact, little thriller that holds up well in its own right some seventy years after its initial screening.

First, the cinema history angle:

          The then thirty-year old Alfred Hitchcock was in post-production of the silent picture Blackmail, (his first thriller since The Lodger), when studio executives at British International Pictures informed him that the revolutionary sound-on-film equipment had arrived and would he care to christen it by remaking Blackmail as a talkie?

          Hitchcock said yes and the film was re-shot using the same cast as on the recently photographed silent version.  There was just one problem: turns out the leading lady (Anny Ondra) had a Polish accent so thick you could cut it with… well, a knife.  Rather than recast a British actress for the part, Hitchcock had Ondra silently mouth her lines while the English Joan Barry stood just off-camera reading those same lines aloud into an open microphone.  It worked, Blackmail became Britain's first full-length talking picture, and the rest, as they say, is history.

Now, to the plot.

          Alice White, daughter of a London shopkeeper, is the girlfriend of Frank Webber (John Londgen), detective of Scotland Yard.  If it's a little excitement Alice is looking for in her workaday life, she's certainly not getting it from the humdrum Frank Webber.

          One night, at a busy restaurant, Alice tries striking up a spark in Frank by striking up a flirtatious conversation with a handsome stranger (Cyril Ritchard).  The plan backfires, Frank and Alice have a nasty fight, and then, as if to show Mr. Frank Webber what's what, Alice departs the restaurant in the company of the handsome stranger.

          The handsome stranger turns out to be of an artistic bent and, after enticing little Alice up to his studio, he offers her a brief introduction to painting nudes, then further entices her to strip down to the barest slip of a slip so that he might paint her.

          There probably wouldn't be many girls who wouldn't know just exactly what was next on the artist's agenda for the evening, but little Alice, shopkeepers daughter, isn't that kind of girl.  Forced to defend her honor, she stabs the man with a handy bread knife, killing him. (So much for fun and games.)

          Alice flees the scene, unwittingly leaving her gloves behind as evidence.  Lucky for her, Frank is assigned to investigate the case.  In due course he finds one of Alice's gloves and, quite unprofessionally, pockets it.  Meanwhile, Alice has been haunted by the images of knives.  She sees the reminder of what she has done everywhere.  Worse still, back at her father's shop, all she can seem to make out of the ambient conversation is the word "knife" --we hear what she hears, a muddle of unintelligible conversation, with only the word "knife" jumping out clearly from time to time.

          In true tell-tale-heart fashion, Alice develops the urge to confess her crime.  To make matters worse, a blackmailer has found Alice's other glove and is threatening to spill the beans.

           Long story short, the culmination of a chase through the British Museum settles the blackmailer problem (a terrific sequence, especially considering what was done on a very tight budget) and Frank has only to silence the lips of little Alice for everything to get back to normal, humdrum as that might have been.