John Dudley Frazer is an agent with British Intelligence.
The activities of this operative, described early on simply as being a "young man", take place during the years of the Great War but since the recorded adventures indicate a considerable number of hair-raising escapades had already gone into his ledger, it is safe to say these occur in the latter year of 1917.
Frazer answers directly to the "chief of a certain department". As that director references both Army Intelligence and Naval Intelligence, it behooves us to stick with the general British Intelligence. This being said, however, it is important to note that Frazer makes considerable use of one vessel from the Royal Navy though he is not actually attached to that branch.
That vessel is mentioned in the name of the collection of Frazer's tales, to wit a submarine with the designation of Z1, described as a "long grim craft". It is captained by Lieutenant Ian Graham and helmed by a Mr. Clark. It is through the use of this underwater craft that Frazer makes a considerable number of trips to the northern region of Germany to begin his missions. Sometimes the aim is somewhere in the North Sea, such as near the headquarters of the German Navy at Wilhelmshaven and sometimes into the Baltic Sea region such as around Kiel.
Frazer, though mentioned as being 'young', is highly experienced in his cloak and dagger trade. His grasp of the German language with its varied accents and dialects is superb and his comfort in traveling all over the country is complete. "It was known at Headquarters that Frazer maintained establishments as far apart as Breslau is from Bremen, and that in a dozen towns and villages he was known under some name or other, had a little circle of unsuspecting acquaintances, with whom he would sit in the evenings drinking his beer and playing skat. In one town he was known as a traveler. In another he was suspected of being a German police official. In Cleve he was Herr Smidt-a Bavarian who came at odd intervals to drink from the Chalybeate Springs."
Back to the use of the Z1 as his means of getting to and from Germany, it is interesting to note that for security reasons, the British Navy has no way of knowing that the boat is in fact manned by its own people heading on missions for the Crown. This means that every time it departs from or returns to its home port, it runs the risk of being depth-charged into oblivion. At the same time the Germans have determined that there has to be a British submarine at work in its waters and the Z1 is actively being searched for by the Kaiser's Navy. This results in a great deal of pressure being put upon the shoulders of young red-haired Lt. Graham.
He is described in one adventure as being "about twenty-six years of age, wears a slight moustache, is about 175 centimeters in height (5'9"), has grey eyes, and a frivolous habit of speech".
"There never was a Bavarian who did not loathe a Prussian."
"You cannot be a secret agent of the Government unless you are [unscrupulous]."