Alec Guinness wears a Tissot Chronograph

Professor Marcus arrives at Mrs. Wilberforce's door with a long scarf, a hairpiece, and a set of protruding false teeth, asking about the rooms to let. Alec Guinness is widely thought to have built the look on Alastair Sim, the actor he believed the part had really been written for, though the critic Philip French saw another model in Kenneth Tynan, prominent teeth and cadaverous pallor and all. From those rented rooms, in Alexander Mackendrick's The Ladykillers (1955), Marcus conducts his fake string quintet of criminals through a security van robbery near King's Cross, a heist that comes off cleanly and then collapses on the question of what to do about the landlady.

Marcus runs the job by the clock, and the film makes the point with an insert: a close-up of his wrist showing a Tissot, a chronograph with three registers on a steel bracelet, the hands reading one minute to one. The dial is the whole identification; no specific model has ever been pinned down, and when watch collectors later passed the frame around, the hands sat close enough to the signature that some could not read the brand at all. It is not even the film's only Tissot chronograph insert; the Barrow Boy, a street vendor with a few minutes of screen time, gets one of his own. The Marcus shot had the stranger afterlife. Christian Marclay's The Clock, the 24-hour montage of timepieces in film, uses it to mark 12:59.