One of the classiest and more low-key thrillers to come from Hammer Films in the late 1950's, The Snorkel is a long way from the studio's more overtly horrific and better-known releases, such as Horror Of Dracula or even The Quatermass Experiment. The pacing is deliberate but never slow, and the thrills all calculated down to the frame, and the tiniest motion of the camera -- and the story is neat enough, with its twist ending (and a final twist that, in the twenty-first century, would probably be skipped), to keep the viewer in suspense right up to the final seconds. The basic set-up of the story is classic crime-thriller in nature, as we watch a seemingly perfect murder being committed; and then we see how the plan unravels, but the manner in which "justice" is done here takes a wonderfully macabre turn in the final two minutes, worthy of Roald Dahl (in fact, recalling his story "A Dip In The Pool" in some respects) at his creepiest, or even one of the old EC horror comics. The makers do compromise on this a bit, in keeping with the time in which it was made -- morally compromised children, even if there may be some ambiguity as to their "guilt," are unacceptable, but the twist is a marvel of its kind. There is also a scene in the ocean, involving an attempt on the young heroine's life by the murderer, which makes one wonder if Steven Spielberg ever saw The Snorkel during his formative years, in terms of how he treats the stalking of the first victim, and the first death in visual terms in Jaws, some 15 years later. Speaking of directors, Guy Green, whose early career was spent working in crews under filmmakers such as David Lean, brings a great deal of class as well as suspense to the procedings, and Mandy Miller makes a convincingly, tragically neurotic young heroine (outdoing her slightly younger contemporary Hayley Mills in this sort of role), while Peter Von Eyck oozes smarmy, disconcerting charm, and Betta St. John is believable as a dupe of the killer, clueless right to the last shot of the movie. Beware shorter edits of this movie, which was cut for its initial US release.