"It's about my book," she says 10 minutes later, once we have sat down in the coffee bar. "I am very worried about it. I want people to buy it but..." Her autobiography, How Do You Want Me?, has just been serialised in a Sunday broadsheet. The first extract, which concentrated on her childhood, made compulsive reading. "No one wants to know about my parents," she says, but she's wrong. Her parents are fascinating. Her father, Edward Wachs, who made frankfurter skins, was an Austrian Jew who had been in a labour camp in the war. Her mother, Bertha, was a fading beauty who had Ruby when she was 48 years old.