John Manning is an agent with British Intelligence.
Working for the Bureau of Special Investigations, a department run by a man the agents call Sir George but everyone thinks of as The Chief, Manning has been an agent in very good standing for over 15 years. The Bureau maintains its anonymity by operating behind the facade of "J Gordan & Co. - Import and Exporter" though Manning has often wondered who the J. Gordan originally was.
Manning is a man of average stature (5'8" weighing 160 lbs) who has had his share of close calls which have included being stabbed, shot, and suffering far too many broken bones, one of which was a jaw that had not truly set back correctly.
During those years of service, Manning has managed to use to his smooth talking and his rugged good looks to capture the hearts of many of the female employees of the Bureau, much to the consternation of the Chief. As the series opens, though, it is easy to see that the dashing Manning can also be a tad petulant when his winning ways do not win, as shown by an encounter with the Chief's lovely assistant who remains quite icy towards the agent despite his best moves.
That character flaw notwithstanding, Manning is a highly resourceful operative, able to work by himself in the most harrowing of situations. Possessing faster than normal reflexes, measured to be 14% better than average, his physical conditioning has kept him alive on several occasions. Even more important to his survival is his above average intelligence, said to be an IQ of 164.
During WWII Manning has been attached to the Royal Engineers. After demustering, he went back to school on his own money attending night classes while he worked a regular job during the day. In 1950 he was offered a temporary job with the BSI and was given a chance to improve his language skills as he served. Two years later his job was made permanent and he began his impressive string of successful missions. Manning speaks German, French, and Russian well enough to pass most scrutiny.