Jake Ord is an agent with British Intelligence.
I do not mention any particular branch or department because as far I could tell from reading the four recorded adventures, that information is not actually revealed. Hints point to it being MI6 but perhaps not. Events in the first escapade would almost certainly rule out MI5. Some other unnamed agency? Perhaps.
Whatever it is, though, Ord is retired from it.
That is a major point in all the affairs we follow him in (so far) and Ord would very much appreciate it if others would remember that he had paid his dues and was now totally out of that game and wanted to stay out and would people please not come around and start shooting at him? Retired, get it?
Just how long before that first 'caper' he said his goodbyes is not expressly stated but someone did refer to his time as a covert operative being in the "dim and distant" path. And when Ord finds himself temporarily on the run in a hilly forest evading men with guns, he chastises himself for having let himself go after all those years - to be fair to him, though, he does pretty darn well so his condemnations aside, he is still in reasonably good shape.
While we are not told exactly what age Ord is, I would put him in his early 50s with his having already lived through a good deal of danger and having survived by skill and determination and - he admits - luck. But he is not yet into the dotage era ready to give up with trouble arrives.
In that first adventure he is living on his own. The second one sees him having moved, for good reason, to the southern part of Portugal and living with the attractive, alluring, but very secretive Magda and from the moment we are introduced to her, she is every bit as important to the recounting as Ord.