* William Gaunt later had a leading role in the ITC series "The Champions"
* Salmaan Peer & Imogen Hassell both appear also in Episode #111 "The People Importers"
* Imogen Hassell also appears in Episode #36 "Sophia". She also appears in the first "The Persuaders" episode "Overture"
* Salmaan Peer also appears in Episode #113/114 "Vendetta for the Saint"
* Ferdy Mayne also appears in Episode #20 "Iris", #28 "The Wonderful War" and #95 "A Double in Diamonds"
* Jeremy Burnham also appears in Episode #49 "The Imprudent Politician" and #85 "Escape Route"
* Robert Crewdson also appears in Episode #74 "The Russian Prisoner"
* Marne Maitland also appears in Episode #16 "Teresa", #41 "Lida" and #117 "Portrait of Brenda"
* Marne Maitland also appears in the James Bond movie "The Man With the Golden Gun" (1974)
* Mary Jones also appears in Episodes #53 "The Contract" and #68 "The Man Who Could Not Die"
* Ray Lonnen also appears in Episode #111 "The People Importers"
*
On the backlot, the back entrance is actually to the left (note the building in the background) of Mike Gregory's flat, not behind it. 
They tried to disguise this with the telephone cell. (0:03)
*
What are they looking at? The painted screen at the back or the two false
bushes in front of the window? ;-) (0:09)
*
A big blooper: You can clearly see the shadow of the camera as it zooms in
on actress Imogen Hassell. (0:12)
*
The hole in the door is already there before you can see the bullet smoke (0:19)
*
The same part of the backlot was used for the Ajax warehouse, London, and the inn in Merrovic. (0:22 and 0:37)
*
Bloody stupid: Why is the inn keeper sitting with his back to the unconscious
pilot? Why isn't Zaglia bound? (0:41)