When he introduced Robert Donat and Madeleine Carroll to each other on the set of The 39 Steps, Alfred Hitchcock invited them to call him by his nickname: ‘Hitch, without the cock’. This was his way of putting actor and actress at ease, says Donald Spoto, but throughout his career Hitchcock used off-colour remarks not merely as playful banter but also to provoke a reaction.

At a photo session to promote one of his most forgettable films, Topaz (1969), Hitchcock asked the German actress Karin Dor, with a lascivious overtone, to put a male actor’s cigar in her mouth. When she demurred, he went further: ‘Come on, Karin, you know you’ve had it in your mouth before.’ 

Yet long before he was a dirty-minded old man, Hitchcock was a dirty-minded young man. As Spoto puts it, ‘his deliberate air of bourgeois respectability … contrasted with unexpected explosions of the crudest, rawest kind of language’. Was this harmless badinage or did it betoken something more sinister beneath the