A fundamental question is posed midway through this narrative by Michael Portillo. Speaking in his guise as a colourfully dressed TV presenter rather than politician, he demands of Natasha Walter as the cameras roll: ‘What did your parents actually achieve?’ They are standing in a nuclear bunker, the site of her parents’ most audacious stunt, but the implication of futility resounds throughout the book, probed most rigorously by their daughter.