He is the head of the "scalphunters", a division of MI6 (called "The Circus" in le Carre's books) dedicated to especially dangerous counterintelligence missions often involving violence or assassinations.
Born to "parents in European banking" with a "small aristo" background (his uncle being Comte Henri de Sainte-Yvonne)[1] Prideaux was raised abroad but attended Oxford, in addition to studying language in France.
He has a gruff demeanor, which Smiley frequently likens to that of a soldier, and often speaks in short, precise sentences; despite this, he is essentially kind, if not harsh, and has a particular soft spot for children.
When the head of the Circus, Control, comes to suspect that it has been infiltrated by the KGB, he sees Prideaux as the ideal candidate to travel to Czechoslovakia on a secret operation code-named "Testify" to interrogate an alleged defector about the mole's identity.
"Testify" turns out to be a trap set up by the mole and his controller to disgrace the Circus, and Prideaux is shot and captured, enduring months of torture.
His gunshot wounds have permanently damaged his spine, which was shoddily repaired by incompetent surgeons, and left him with a curvature resembling a hunchback, although he keeps fit through solitary games of squash and walks through the surrounding countryside.
A year following Testify, George Smiley is tasked by Whitehall with identifying the mole, after one of Prideaux's Scalphunters, Ricki Tarr, escapes Hong Kong with information confirming his existence.
[5] His portrayal was considered a "serious disappointment" by author Le Carre[6] but is in keeping with the Prideaux of the book, presenting him as a rough-edged, no-nonsense military man who speaks in short, clipped sentences and who is sometimes overtly aggressive to Smiley.
In the film version, Prideaux is captured at a cafe in the Hungarian capital of Budapest, rather than in the woods near the Czech city of Brno as in the book and series.