A caricature of Richard Wagner in conversation with Hitler adorns the wall. Books on Liszt, Nietzsche and the Holocaust rub shoulders on the shelves. Various gifts from rabbis sit next to a gold sculpture inscribed by patrons of the Anne Frank Prize.

I am standing in the basement of the home of Gottfried Wagner, great-grandson of the composer and self-confessed black sheep of the Wagner family. Cramped and poorly lit, it feels like a bunker to which Gottfried can retreat whenever he wants to address the issues that have long dominated his thinking – his composer-ancestor’s anti-Semitism and his family’s links with Hitler.