Trivia

The Leicester Square Odeon premiere of Amos Klein's latest Charles Lake film "Sunburst Five" features in Frug's copy of "Screen Album", where it states that Roy Baker is the movie's director. This is an in-joke, as in reality, Roy Ward Baker directed this movie. The article notes his filmography includes The Queen's Ransom (1966), which itself is the title of one of Baker's many directing jobs on the third season of the series.

Although the release date of this feature length version was December 1968, the fashions and style suggest that it was filmed a lot earlier. The title sequence indeed shows a copyright year of 1966, indicating that this was filmed during the period of the first colour series of Le Saint (1962). However, the two part episode that made up this feature length version, was not aired until the latter part of the final season. In the rest of those episodes for that final series, Roger Moore's hair is noticeably longer, darker and with longer sideburns.

Warlock's car is a 1961 Humber Hawk Series II.

Leslie Charteris wrote that the film "fulfills all the promise of the synopsis, and the dialogue has a crisp sparkle which has all too often been lacking in other scripts. [...] But it is simply a splendid job. I hope there will be a lot more scripts like this".

John Kruse admitted that he had no idea what Harry W. Junkin's "additional scenes" were.