What is the setting of The Honourable Schoolboy by John Le Carre?

The novel takes place in many different locations. The Circus, Smiley, and his team all remain in London for the majority of the novel. The reader often accompanies Smiley on tours of London as he walks the street in an attempt to think through the evidence presented to him in the case. Smiley's team, on the other hand, spends a great deal of time in Circus headquarters where they scour files for cases that Haydon may have squashed prematurely in order to hide a Russian connection.