I wrote three mysteries and then a contemporary spy novel that was unbelievably derivative - completely based on 'The Conversation,' the movie with Gene Hackman. Amazingly, the character in the book looks exactly like... Gene Hackman.
Le Carre's voice - patrician, cold, brilliant and amused - was perfect for the wilderness-of-mirrors undertow of the Cold War, and George Smiley is the all-time harassed bureaucrat of spy fiction.
I invented the historical spy novel.