A great overview of Cracker in Wiki:
Fitz is a classic antihero: Scottish of Irish origin, alcoholic, a chain smoker, obese, sedentary, addicted to gambling, manic, foul-mouthed and sarcastic and yet cerebral and brilliant. He is a genius in his speciality: criminal psychology. As Fitz confesses in ‘Brotherly Love’: "I drink too much, I smoke too much, I gamble too much. I am too much."
I think a great actor is just like a great red wine - improving with age.
Strangely enough I had recently looked for news of Robbie as there had been no news of him for a while and read he was confined to a wheelchair and awaited an operation for which he had dieted considerably.