* Stanley Meadows also appears in Episode #35 "The High Fence" and #72 "The Queen's Ransom"
* Stanley Meadows also appears in the episode "The Man in the Middle" of The Persuaders
* Tony Beckley also appears in Episode #23 "The Saint Plays with Fire"
* Tony Beckley also appears in the Roger Moore movie "Gold" (1974)
* Johnny Briggs also appears in the episode "Someone Like Me" of The Persuaders
* In the German dubbed version the mystery of the anonymous letter writer is completely spoiled because of the easily recognizable voice you hear in the telephone call. (It's already rather easy to recognize in the original version.)
*
The text of the article doesn't quite fit with the headline of the article - the headline about Marcia's death was just glued over the original newspaper. (0:00)
*
The actress on the photo of Marcia
does not appear in this episode... 
...but she does in Episode #38 "The Ever-Loving Spouse" in the bar scene at the beginning, even in the same dress! She only appears very briefly in that episode. She was played by actress Eve Eden who went uncredited in this episode. She is also the water-skiing woman in Episode #7 "The Arrow of God". [The information that this is Eve Eden was submitted by "Mr. X"]
*
The photo of actress Jeanne Moody on the wall... 
...was also used in Episode #38 "The Ever-Loving Spouse" [Submitted by Wojciech Trojanowski] and... 
...in Episode #14 "Starring the Saint".
*
The actress on this photo is Yvonne
Romain from Episode #21 "The King of the Beggars".
*
This shot with the studio exterior
does appear twice in this episode - at 0:05 and 0:23 - and was also used in Episodes #14 "Starring the Saint" and #54 "The Set-Up"