God Does Not Own This World: Terry Nation envisaged a dark, action-adventure political thriller about the breakdown of social order; producer Terence Dudley wanted a far more optimistic and character-based series about rebuilding society. Early episodes about a lawless society and self-appointed dictators carving up the country gave way to the heroes having a safe, self-sufficient base camp where external threats were fairly easily repelled. Nation finally quit after the first season when his ideas were ignored and his intended lead couple Abby Grant and Jimmy Garland were dropped to make self-sufficiency expert Charles Vaughan, created by Dudley's preferred main writer Jack Ronder, the lead character, with Nation writing a novel showing where he wanted the storyline to go instead. The third season, with Martin Worth as head writer, returned the sense of lawlessness but its endings of the heroes setting up a benevolent central government and restoring electrical power was far from what Nation originally intended.
Terry Scully played Vic Thatcher in "Genesis", "Spoil of War", "Law and Order" and "The Future Hour". After Scully had a nervous breakdown, Hugh Walters assumed the role in "Revenge" and "A Beginning".
Tanya Ronder played Lizzie Willoughby in Seasons One and Two while Angie Stevens played her in Season Three.
Sally Osborne played Agnes Carlsson in her first appearance in the Season Two episode "New World" while Anna Pitt played her when she became a recurring character in Season Three.
Real-Life Relative: John Millon is played by Stephen Dudley, the son of the series' producer Terence Dudley, while Lizzie Willoughby is initially played by Tanya Ronder, the daughter of one of the series' writers Jack Ronder. Ronder wrote "Gone to the Angels" in which John and Lizzie were introduced.