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".
Robert Lindsay was the original choice for Fitz but turned it down, as he did not want to become too associated with heavy, darker drama characters.
Robbie Coltrane was primarily known as a comedic actor before the series. He was cast based on his performance in Alive and Kicking (1991).
Jimmy McGovern initially pictured Fitz as being a "thin, wiry man with a sense of danger - a John Cassavetes type" who looked like he had spent some time in the army.
Fitz was named after the English poet and writer Edward FitzGerald, according to series creator Jimmy McGovern.