Fitz is never seen driving and is always driven by others. The reason is never explained in the series. But in the book "Cracker: The Truth Behind the Fiction", it says that "He's never trusted himself behind the wheel of a car - its just too tempting to put your foot down and close your eyes and gamble that you won't hit anything before you've counted to twenty".
Fitz was named after the English poet and writer Edward FitzGerald, according to series creator Jimmy McGovern.
Robbie Coltrane was primarily known as a comedic actor before the series. He was cast based on his performance in Alive and Kicking (1991).
The "Men Should Weep" storyline was originally conceived as a plot for Prime Suspect (1991), in which the series' protagonist, Jane Tennison, was raped.