DJ Johnny Drake's final disc to be spun is "He Who Rides A Tiger", by Patsy Ann Noble. This is another name for Trisha Noble, who appears in the episode as Susan Wade. The record's genuine, and was released in 1966 on the Polydor label (BM 56054).
The exterior footage of the Jolly Roger was shot at Red Sands Fort, offshore from Whitstable. The rig had been home to genuine pirate stations Radio Invicta and KING Radio, and at the time of shooting was used for broadcasting by final occupants Radio 390 (named after their broadcasting wavelength). The imposing structure, built in 1943 as one of the three Thames Estuary Maunsell Forts (WWII anti-aircraft defense installations) was later used by the Doctor Who (1963) team for their 1968 story "Fury From the Deep".
Director Don Chaffey was stricken with acute appendicitis within an hour of setting foot on Red Sands Fort, where the exteriors were shot.
The final monochrome episode of the series to be filmed.