Oreste Pinto, aka Spycatcher, is an agent with MI5.
At least that is what one blurb on a publications of his accounts describe him.
In the opening to the two dozen plus radio dramas about those same adventures, we are told, "Spycatcher - a series of true stories of the unceasing search for enemy spies in wartime, based on the memoirs of Lt. Col. Oreste Pinto of the Allied Counterintelligence Service".
Into this compendium of fictionalized espionage agents I enter an actual real-life person for membership but I do so because his casefiles formed the basis for a series of fictionalized - or likely more accurately dramatized - adventures. How much of what we have to view in the television broadcasts or listen to in the radio ones is not known and for this matter, not too important. Whether they stick to hard facts or add elements for entertainment purposes, they are certainly worthy of following because Pinto was an interesting man with an interesting career.
According to Wikipedia, Pinto was a Dutch Counter-Intelligence officer and a Lieutenant-Colonel in their military when he left the Netherlands to work with the British against the Nazis who had invaded his country. Prior to that move he had worked in the Intelligence field for nearly 30 years, getting his start in 1913 for the French Deuxieme Bureau.
Throughout the War he worked with MI-5 as an interrogator, making it his specialty to vet the hundreds of refugees that fled Continental Europe for Britain. As he tells us in his recounts, most of those seeking asylum were truly what they claimed to be but more than a few were German spies made to look like the down-trodden to get acceptance prior to reporting back to the Fatherland anything and everything they could learn.
Exactly how successful he was will always be uncertain but there are several blurbs stating that General Dwight Eisenhower, later U.S. President, once described him as "the greatest living authority on security".