Other mistake: At the end just as Carter is about to be shot, he is facing the sea as he goes to throw his gun away. At this point the gunman fires and hits Carter square in the forehead. The position of the gunman is shown as being behind Carter and to his right (this is seen when the gunman lines up to take aim). Even though Carter leans back as he throws his gun away ,he would have been hit somewhere on the right side of his head or temple at best.
Continuity mistake: The Ford Cortina that Jack Carter drives in the film changes number plates. The first time we see it in the film (tailing Kinnear's Cadillac) its registration number is YBB372H. For the rest of this car's appearances in the film, the licence plate is YBB371H. The front bumper is also missing when Carter first drives to Kinnear's house, and mysteriously reappears before being ripped off in a later scene.