Gil Hazzard is a movie stuntman.
Whether it is leaping off a tall building for an awesome shot, and hopefully landing right on the airbag below, or driving a speeding car off a pier to land on a departing boat, he is the man to call for a great shot in a movie. He is meticulous in his planning but also incredibly daring in his execution.
Hazzard is actively working as a stunt driver for a movie production company, performing some of these very impressive and quite dangerous moves, all to make the film extremely exciting, when we first meet him. His pleasure at having completed the stunt to the director's happiness is abrupted ended when he is approached by a former associate at British Intelligence, a bowler-hat-wearing poshly-dressed sour-looking man named Carmody, with the unwelcome news that "the Gov'nor's got a job".
It is at that point we learn that Hazzard, quite an apt name for someone in his profession, was for many years an agent with a branch of British Intelligence and the 'job' that he is being called back for isto help in a hostage situation where the perpetrator is another former agent named Valentine, referred to as Hazzard's old partner. That is how we learn the reason Hazzard is a former agent, namely that it was men like Valentine and Hazzard who were the ones ordered "to go out and pull the trigger" and that Hazzard "got out before the job got to [him]". He had simply had enough of working for what he called a "Department of Dirty Tricks".
Unfortunately, the Guv'nor has the attitude that no one ever walks out on his department and that Hazzard will be brought back into the fold no matter how much he refuses.
When offered a chance to return to work for the Guv'nor, his old boss, Hazzard states, "I quit the Service because I didn't like the smell - and it hasn't improved".