It is November 2009 and I’m in a new restaurant on Fairfax Avenue in Los Angeles called Animal. I have been in the city for three weeks, serving as a judge on a TV food contest, all British piss and vinegar to the familiar American gush, and I’m missing my family terribly. No matter, for here on the menu is roast bone marrow with parsley salad, the dish made famous by the chef Fergus Henderson at his Clerkenwell restaurant St John. His guiding principle: “If you’re going to bang an animal on the head it’s only polite to eat it all.”