Blake Drysdale is an agent with British Intelligence.
Not officially, of course. That would not do at all; not considering what Drysdale was also known for doing. To put it simply, as the blurb on the first recorded adventure does about him, "Blake Drysdale is an aviator, smuggler, and all-around crook". These were activities that definitely would not be anything Her Majesty's Government would want associated with them. They were, of course, several 'asperations' that could come in handy for the type of work they would find needed doing.
Mind you, Drysdale admits freely about his illegal actions but does have a code that he will not break. "I run a professional operation and I prefer to avoid making enemies, especially of men with guns. It's not healthy and in the long run I find a reputation of respectability to be far more profitable than one-time gains." Also, he draws the line on drug smuggling, at least the 'hard stuff'.
The time period the adventures of Drysdale takes place is the mid-70s. When we first meet him, it was April 22nd, 1975 in Saigon. In a week the city would fall to the forces from the North and life for everyone in the southern city would change forever. That would, of course, mean Drysdale.
Drysdale is described as having "dark eyes set in a dark face, speaking of sub-continental ancestry. He was of mixed blood, British Indian, and probably disinclined to discuss it". He walked with what some might consider a swagger but was in fact a ever-so-slight limp. He was not a tall man by any means but he had an "ease and economy of movement that marked him out as a danger-man; one who could hold his own, who you didn't start a fight with unless you really wanted a fight." One other interesting trait was that Drysdale opted to keep his language clean; he "wasn't a swearing man, though fighting the urge was occasionally difficult".
He never expected to begin a relationship with a "legitimate" clandestine organization but once he was thrown into contact with one, the connection just kind of stuck.