Paul Chavasse is an agent for The Bureau.
The Bureau is a highly secret member of the British Intelligence community, in place to handle those cases which are too sensitive for more known agencies like MI-5 or MI-6. The Bureau operates out of a fine house in London disguised as Brown & Company, Importers and Exporters. The department is a small one with just a few operatives. In the first adventure, Chavasse complains to the "Chief" when given a new assignment fresh off a particularly hard one and asks why not send another agent, mentioning two in particular, only to be told that one was likely dead and the other relieved due to stress, leaving Chavasse to take the job.
He has for many years prior to the start of the series worked for this clandestine arm of the British government. He has been sent around the world to handle cases that either others have failed in or that others don't want to touch or be seen touching.
Chavasse, the product of a British-French union, is said to speak more languages than "you've had hot dinners." He also has achieved, apparently, several university degrees over the years. All this while still being one of the most deadly enforcers the government had. It was the languages and the education that attracted the Bureau to recruit him, pulling him out of a professorship in a provincial university. He longs for the chance to return to that quiet life but he knows he would quickly grow too bored to enjoy it.
Some of the original publications of the chronicles of his actions were reprinted with additional material, taking place during the present and reviewing the past events. According to these, Chavasse would go on to be knighted by the Queen and serving for over 20 years, after his time with the Bureau, as a Bureau Chief in Belfast during the heat of the IRA troubles.