Alan Brady is an agent with the British Secret Service.
"Calling Z.9" is the catchphrase most associated with this young but highly experienced and capable operative. Apparently sent out over the airways via likely a ham radio, this call would summon the man to appear at his Chief's headquarters for a briefing on yet another exciting and always dangerous assignment.
We learn immediately by both the image displayed at the beginning of each segment of his adventures and by the text often starting each mission that Brady, a blond-haired athletic man, is an "ace motorcycle racer". His fondness for the two-wheel mode of transport is made obvious on several occasions. Interestingly, though this was back over a half century ago, Brady was smart enough to routinely wear a helmet while riding, even when he was heading into situations where knives and guns and blunt instruments were readily available to those wanting to accost him.
Throughout the numerous operations Brady was a part of, we learn a lot about his bravery and his audacity but we learn virtually nothing about his life before and during his adventures, outside of work. The lone exception is that he was an avid and successful racer on motorbikes and still retains a great love of them.
Though the missions we are shown of this intrepid hero were presented in the 1950's, they all appear to take place prior to the Second World War, with the exception of one or more at the end of the sequence. In that instance(s), the year is 1939 and Brady has joined the elite Special Air Service (SAS). He holds the rank of Sergeant and uses his abilities gained as a Secret Service agent to handle dangerous missions behind enemy lines where capture meant certain death.