Xavier Flynn is an assassin for the British Counter-Espionage Department.
Thirty-six years of age at the time the major events of the series begin, he was recruited as a young man of twenty-one while performing his national service with the Fusiliers in Malaya. When the Department decided an assassin was needed, at the top of the list was the name of Flynn due to his willingness to kill on command. Flynn was not one to ask too many questions when given an order. This made him the first choice for the new position. Though other agents would also be hired for this lethal section, Flynn remained the best and most feared.
Flynn is described as a man who greatly loves wine, women, and song and partakes of each liberally and often. He is also a devout Catholic who routinely seeks Confession and tries to atone for his sinning. Most of all, Flynn thinks of himself as a solid member of the working class and is a man who leaves the decision-making to others.
On the one hand he is a party animal. On the other, he is a man concerned with his soul. And he is always a man who is willing to kill at the drop of a hat working for an organization that has decided there are some enemies of the state just best eliminated. Leading the enemies list is an organization called FIST, Fear Insurrection Sabotage and Terror, dedicated to the destruction of all free societies to put order back into the world.
Interestingly, while the two books in this series didn't come around until the mid 70s, the Angry Young Men style of writing that the author help introduce twenty years before probably had an effect of spy writers to come later. Instead of agents who were upper crust and went to the best schools, these new spies were from common beginnings and often didn't trust the bosses.