Last show of the series.
Composer Laurie Johnson closes out the series with some brand new music, including a melancholy theme for euphonium and brass band, and some psychedelic source music for the underground orgies.
It's heavily implied that John Steed and Tara King are newly married at the end of this episode. This mirrors the movie version of the film where at the end it's implied John Steed and Emma Peel are married.
Cordell wears the same Guards tie as Colonel Stonehouse wears in "Take Me to Your Leader" and Wainwright in "The Rotters".