Continuity mistake: During the opening sequence, a white car parked outside the prisoner's London flat disappears between shots as he drives up in the yellow Lotus and walks to the front door.
Continuity mistake: While the prisoner is packing for his trip (in the opening title sequence), a beach photo placed in his travel bag rotates itself into a different position between shots.
Continuity mistake: In both the opening and closing sequences, as well as in footage used throughout the series, "Rover" leaves the ocean floor as a transparent sphere, but arrives on the surface colored his usual opaque white.
Continuity mistake: In the opening sequence, prior to the Prisoner being spirited away to the Village, the holiday photo inside his briefcase appears to turn 90 degrees between two quick edits.
Answer: It's even more obvious than you think, you know who number 1 is in the very first episode. When 2 replies to the question "who is #1?" Change the way he answers from you are number one (in the monotone or accented answer to, "You are, number 6. The comma gives you the answer. #6 is #1. It's the tone of the answer.