After a preview screening of this film, an aghast Head of Columbia Pictures, Harry Cohen, offered a thousand dollars to anyone who could explain the plot. There were no takers: even Welles himself said he would have been struggling. What we have instead of a straightforward narrative is a film noir poem whose atmosphere of clammy pollution evokes a moral as well as physical environment and whose motifs of sea, animal imagery and mirrors suggest the instability, ferocity and duality of its emotional world.

‘It’s a bright, guilty world,’ says the film’s Irish hero (Welles), an innocent who has been hired as a sailor on a millionaire’s yacht called ‘Circe’ and who is lured by a dangerous enchantress (Rita Hayworth) toward the rocks of nihilism and corruption. Everett Sloan’s crippled lawyer, Bannister, and Glenn Anders’ insane, reptilian Grisby are two of the director’s most memorable villains. And the Hall of Mirrors finale is the director’s most widely imitated set-piece — a technical tour-de-force and a scene that relishes the piling up of layer upon layer of visual deception: a metaphor for the treacheries that dominate the film.