 Despite his age, he is one of the more competent members of the platoon.Joe Walker was played by James Beck in the television series and seven episodes of the radio series, and by Graham Stark for five radio episodes, with Larry Martyn for the remainder of the radio series.A black market "spiv" (he called himself a "wholesale supplier"), Walker was the only fit, able-bodied man of military age in Walmington-on-Sea's home guard.