The Corridor People are agents with Department K.
That agency is an obscure small organization in the British Intelligence community. Small because there are just, apparently, a handful of people who comprise the group. Obscure because it is, again apparently, little talked about. Both of these aspects are well earned. An agency as bizarre and, to be honest, unpleasant as Department K is should have many people forced (or allowed) to work for it and, for the good of the British people, it is best that it is not spoken of very much.
Department K is run by a man known simply as Kronk. He is described, kindly, as portly. He is also said to come across as someone who falls fully in the jovial category because he is often seen or heard letting go with a raucous belly laugh at the slightest provocation. Once one looks deeper into the actions of this former police official, that laughter takes on a whole new and quite creepy aspect. Malicious is one adjective that could be used and demonic would not be unwarranted.
As the main, and possibly only, field operative working in Department K, there is Phil Scrotty. That interesting last name is shouted quite often by Kronk when he is excited or angry but it seems that more often than not, Scrotty is not in the office. Where this man, who it seems would rather be a Sam Spade-ish private investigator, is when summoned varies but the key point is that Scrotty is never where his boss wants him to be. Wherever he might be, though, it is safe to bet that he is pulling a fast one on someone because it becomes clear that a person should never trust Scrotty - ever.
Also working for Kronk but in more of a police role than that of an operative are the perpetually white trenchcoat-clad, fedora-wearing pair of Inspector Blood and his assistant Sergeant Hound. Tweedle-dee and Tweedle-dum comes to mind for these two quite incompetent coppers, both of whom seem to be aware of their failings and not much carrying about them.
The last member of Department K that we meet in the few recorded adventures we have of it is Miss Dunner, a middle-aged acerbic dour assistant to Kronk. She comes across as his right-hand person and might well be but we also learn that she has another role with the agency and one she is very good at - assassin.
Department K's main reason for existence, evidence tells us, is to try hard to combat an extremely nasty and very intelligent enemy of the state named Syrie Van Epp. This woman of Persian descent, who looks more Scandinavian to me, is bloodthirsty and heartless devious. She is also obviously a lot better at her job that Department K is at its.