“A theme of the novel,” le Carré wrote to his aunt Ella Haymes, who along with her sister Ruby was upset by the book (or at least its reception—they hadn’t read it), “is that hypocrisy thrives upon the silence and the goodheartedness of respectable people, and that deceit, when it passes unchallenged, can be bestowed upon one generation by another.”

https://www.bookforum.com/print/2904/the-correspondence-of-spy-turned-novelist-john-le-carre-25148