One of the most playful of Hitchcock's British thrillers, this was adapted by Charles Bennett from Joseph Conrad's novel The Secret Agent, which in fact had been the title of Hitch's previous film. The foreign saboteur at large in London is cinema-owner Homolka, and in part at least, his profession allows Hitchcock to indulge in the sort of movie-movie self-consciousness of which he would become the object some 40 years on. The film proceeds from the point where the lights go out (Battersea power station is the first sabotage target), and even includes a telling screen-within-a-screen homage to Disney and the Silly Symphonies. The narrative's a bit perfunctory, but is neatly overbalanced by the joyously rule-breaking sequence of a boy, a bus and a time bomb.
Cast and crew