The best example of spy craft on TV was this British series from the late 1960s, with a central
character who hated his job but realised his life expectancy was nil if
he left the service. This show was a gripping thriller that emphasised
the psychological aspects of the job, but could dish out the violence if
required, with an iconic performance by Edward Woodward in the lead role.
The last few episodes formed a story-line that was a cracker, where the ruthless Russian assassin pleads with Callan to finish him off before he gets turned over to the interrogators. As a reviewer said "presented a picture of British secret service methods that left a queasy feeling in the stomach".
While the pilot still exists, many of the episodes from series one and two have been lost. For a long time the only way to see these Black and White episodes that remain is the bootleg copies that came up often on web auction sites, but UK DVD publisher Network released the surviving B/Ws on DVD: Callan - the Monochrome Years.
Written by the series creator James Mitchell, the first four of these - A Magnum for Schneider, Russian Roulette, Death and Bright Water, and Smear Job - are well worth tracking down, but the fifth - Bonfire Night - has been less popular with fans of the series and can only be recommended to die-hard collectors who like to have the whole set.
James Mitchell did a series of short stories on Callan in the 1970s.