Anna Cottrell's documentary looks at three high profile sports referees, and what makes them tick. Billy Bowden, the showman of international cricket, took up umpiring when arthritis prevented him from playing. Southlander Paddy O'Brien left the police to become one of the world's top rugby referees. Steve Walsh began refereeing when a neck injury curtailed contact sports. The Whistle Blowers explores the qualities that made them successful, and includes interviews with their families, colleagues and adversaries. The young Walsh had an eventful and controversial career ahead of him.