When Julian Borger’s father took his own life in London in 1983, his family assumed it was linked to recent events. Robert Borger, a lecturer in psychology at Brunel University, had been passed over for a promotion at work and, after an ultimatum from his wife, Wyn, about his infidelity, had walked out of the family home. But then Borger Jr telephoned Nancy Bingley, who lived in Caernarfon in Wales and had fostered Robert after he arrived from Austria in the late 1930s as a Jewish refugee. On hearing that he had killed himself, she said: “Robert was the Nazis’...