In 1972, I was a post-grad student at Oxford when Idi Amin expelled all Asians from Uganda. Everything fell apart. I thought I’d have to quit university. Professor Hugh Blaschko, a world-famous German Jewish pharmacologist and his Quaker wife, Mary, offered me rent-free accommodation. I lived with them for seven years and grew to love them. The Nazis had murdered many of his family members. Some were in a painted family portrait in their living room. He told me what Berlin was like before and after Hitler rose to power. Those stories stay with me. The recent attacks on Jewish...