Patrick McGoohan once stated in a 1977 interview that this episode was his favourite of the series.
This was originally scheduled as the final episode of the first season. However, after the show was canceled, Patrick McGoohan used it as the springboard for the final episode he shot to sum up the story.
No 6 is revealed to be a World War II veteran of the RAF who had bombed Germany.
The script was originally credited to “Archibald Schwartz”. Patrick McGoohan used a pseudonym because he felt that the script would be ridiculed.
The characterization of Number Six in this episode is significantly different from previous episodes. During the series, Number Six’s initial fury and apprehension towards the Village eventually transitioned into the manner of a suave, obstinate rebel who now carried himself with assurance and certainty in resisting the Village. However, in this episode, Number Six is edgy and tense, pacing back and forth in his kitchen without the casual ease of previous episodes, and his interactions with the Villagers have become bizarre, with his accosting the Umbrella Man who seems eager to avoid him. As “Once upon a Time” was shot sixth and held back as a potential end-season cliffhanger, it may be that plans to develop Six’s characterization to this state were curtailed by the sudden cancellation.
No 2 calls No 6 a “lone wolf”, and says that lone wolves belong in the wilderness, not in society. “Lone Wolf” was the code name of John Drake in the series Danger Man (1960), and some fans see this as more evidence for No 6 being that character, which is something Patrick McGoohan denied, but George Markstein affirmed, and was carried into The Prisoner (1967) promotional materials. Markstein was involved in the earliest stages of the development of the Prisoner, but later quarreled with McGoohan.