The hero of the series is an agent with British Intelligence.
It is necessary to be that vague when talking about the main character because the reader never learns the gentleman's name in any of the so far three adventures recorded about him. That is, of course, quite strange for any tale because even if the author chooses to not mention the man by name, it is extremely rare that the people dealing with the man should never one mention so much as a nickname.
And nicknames is something that the man in charge of the hero gives everyone. These amusing sobriquets are often derived from some facet of the person such as a character named Sopwith being tagged 'Camel' and a man who recently visited a call girl being dubbed 'Casanova'. Each person the boss, named Bartholomew Meriwether, deals with or about invariably is honored with such an identification but if the hero is ever given one, it, too, is never mentioned.
The mystery continues with who exactly his employer is. I mention British Intelligence because the people paying his salary are definitely British and most certainly working in the intelligence field but they are not MI-5 nor are they MI-6 though they have a lot to do with the latter, called VC or VX (for Vauxhall Cross, I imagine). There is at least one mention of Meriwether having actually worked at VC once but it is not certain if he still does. Early in the first adventure, a representative of Meriwether states that they were from the Foreign Office which may very well be correct but could just as easily be misdirection.
Whoever the hero works for, the organization works at some fairly high levels as Meriwether is a man of means with a lot of connections in the highest circles and moves about at the altitude without hesitation. Obviously he belongs there.
Which is certainly not something one would say about the hero. This man is very much a common guy and enjoys it. He is not used to the finer things and when he lucks into having access, he readily partakes of them but he knows such things are only temporarily available and when they go away, he would tend to shrug and go back to life as he knows it. He is ever the pragmatist.
The hero becomes connected with Meriwether and his people, especially the lovely Charlotte Miller, when he was unceremoniously let go from the Royal Army with a dishonorable discharge for gross insubordination. His offense was nearly killing a senior officer, something the brass take a very dim view of but which seemed justified to the hero. The nearly departed officer had chosen to send the hero on a mission knowing that at the time the hero's mother was dying in a hospital. The hero was told of the condition only after the mission was over and after the mother had died. The hero took exception to that and even greater exception to the officer's smug attitude. A one-sided fight resulting in a nearly broken neck and the hero was out of work.
One week later, the hero is invited to a mysterious (to him) meeting with Ms. Miller and two other chaps and offered a job. It was to go somewhere and kill someone and no reasons given which made the hero ponder for a moment but he was out of a job and work was work. He accepted.