Like all transformative revolutions, Britain’s Sixties was an episode of highly influential myth-making. This book delves behind the mythology of inexorable ‘secularization’ to recover, for the first time, the cultural origins of Britain’s moral revolution. In a radical departure from conventional teleologies, it argues that British secularity is a specific cultural invention of the late 1950s and early 1960s, which was introduced most influentially by radical utopian Christians during this most desperate episode of the Cold War. In the 1950s, Britain’s predominantly Christian moral culture had marginalized ‘secular’ moral arguments by arguing that they created societies like the Soviet Union; but the rapid acceptance of ‘secularization’ teleologies in the early 1960s abruptly normalized ‘secular’ attitudes and behaviours, thus prompting the slow social revolution that unfolded during the 1970s, 1980s, and 1990s. By tracing the evolving thought of radical Anglicans—uniquely positioned in the late 1950s and early 1960s as simultaneously moral radicals and authoritative moral insiders—this book reveals crucial and unexpected intellectual links between radical Christianity and the wider invention of Britain’s new secular morality, in areas as diverse as globalism, anti-authoritarianism, sexual liberation, and revolutionary egalitarianism. From the mid-1960s, British secularity began to be developed by a much wider range of groups, and radical Anglicans faded into the cultural background. Yet by disseminating the deeply ideological metanarrative of ‘secularization’ in the early 1960s, and by influentially discussing its implications, they had made crucial contributions to the nature and existence of Britain’s secular revolution.