Sachs plays a key supporting role in the Karla Trilogy, Tinker Tailor Soldier Spy, The Honourable Schoolboy, and Smiley's People.
From her vast memory, she provides him with important clues in Tinker Tailor;[3] when he must rebuild the Circus after its betrayal, Sachs returns happily to her work despite her failing health.
She is crucial to the unravelling of the paper trail at the centre of The Honourable Schoolboy and retires after their success against Karla, this time permanently.
She is taken care of by her female lover, a former Circus agent named Hilary; despite her objections, Connie agrees to speak with Smiley, and provides a key that leads to the eventual victory over Karla.
Although she worked in domestic intelligence (unlike the fictional Connie), she was reportedly the first to alert British authorities that double agent Kim Philby had past associations as a Communist.