An article published in in-house Central Intelligence Agency journal "Studies in Intelligence", presumably written by agents under pseudonyms, called it "one of the most enduring renderings of the profession". It does question the "organisational compression" involved in the form of a large organisation, which the SIS would be, being reduced to a handful of senior operatives playing operational roles, but admits that this "works very well at moving the story along in print". However, the idea that a major counter-intelligence operation could be run without the knowledge of counter-intelligence professionals, an allusion to Smiley's investigation progressing in an undetected manner, is deemed an "intellectual stretch".