Michael Jagger is an agent for British Intelligence.
As the series opens, Michael Jagger (never Mike or Mikey) is 38, out of a job and getting very bored. For years he had been at the top of the espionage game, willing to take enormous risks to get the job done and even more so for the excitement. He had worked for an agency of British Intelligence manned by a person known as the Master and he was the top agent. Then on a critical and dangerous mission, he had pulled off the impossible. Expecting loud applause upon his return, he was instead chastised for recklessness that, in the Master's opinion, had cost the lives of two men who needlessly had died. Instead of laurels, he was given a boring desk job. He quit.
The mundane jobs he found after that were so desperately dull that he almost screamed for excitement. But he wasn't going back to the Master. He didn't have to. He was moderately well off from a trust fund from a father whom he didn’t care for but who had made a considerable amount of money through various dishonest endeavors and then left it to Jagger when he died. With the inheritance and the pension that the Department had given him upon discharge, he didn’t have to work. He could lie about and drink too much and drive his beautiful Lotus Cortina sports car too fast and chase too many beautiful women who would love to catch him.
But that would be boring. And the other jobs that he thought about or looked at were all the same - boring. No matter. He was not going back to the Master, ever.
Except for the three missions detailed in this series.