A good, solid British golden oldie from director Roy Boulting tapping into the, usually American, fear of communist fifth columnists attempting a takeover. A series of explosions at dockyards that is clearly sabotage brings in a wily Scotland Yard detective (Liam Redmond) and MI5 who soon start to build a cache of suspects. The film has a neat suspense building narrative with police surveillance and subtle visits to cause fear amongst the conspirators. They target a weak link who ends up getting kidnapped by his erstwhile friends and the clock begins ticking as the bad guys plot to blow up a power station. There's a gritty gun battle in the films climax and a smarmy politician gets his comeuppance. There's a quaintness to the images of the police use of telephone kiosks, morse code and rooms full of card indexes in this modern day and yet the film retains a good thriller narrative. Today it's an example of British film making when there was a fully established and world wide respected industry that produced such great entertainments as this. Worth checking out for the sheer nostalgia of the experience.
This is not the only thing likely to blow up in High Treason (1951). Made by John Boulting a year after his splendid Seven Days to Noon, this, too, has an apocalyptic tone as troops mass in Eastern Europe along with fatal sabotage at the Docks.
Many are the settings which play a part in all this, from Kenneth Griffith's electrical-repair shop volubly frequented by Dora Bryan to the very corridors of Parliament – with many an exterior scene of a bustling capital.
The suspense is terrific, within each scene and as a whole (a rare achievement in cinema), which makes it as good as Sabotage, perhaps better. Stock figures transcend such types, whether stout detectives, an alluring woman (Mary Morris) or the palpably serious audience at a classical music society (with this a pivotal point of the plot, it is fitting that the film has a fine score by John Addison).
Deserving of the term noir, much taking place after dark, it owes much to Gilbert Taylor's cinematography (he had worked on Seven Days to Noon and would make Dr. Strangelove and A Hard Day's Night distinctive).
How well known is this film? Nobody should pass up a chance to see it.