Jamie Foreman (Lennie Taylor) is the son of Freddie Foreman, a notorious gangster who used to run with the Kray Brothers. His life was the basis for the movie The Long Good Friday (1980).
The two actors who play the "gangster" at the two points in his life are 7 inches different in height.
Malcolm McDowell's older version of Gangster is called "Gangster 55" in the script to differentiate his lines from that of Paul Bettany's young Gangster. The "55" represents Gangster's age in the present day.
A Superman logo is seen at one point. Malcolm McDowell has done voice work for Superman cartoons, primarily as the character Metallo.