He specialises in "nose to tail eating", simply-prepared dishes with local, seasonal ingredients and frequently using parts of the animal, brains, intestines, hearts, you won't find under shrink-wrap in the meat section of your supermarket.
US celebrity chef and author Anthony Bourdain considers Henderson his favourite chef and says St John's signature dish, roast marrow bones with parsley salad and toast, is the meal he would most like to eat before he dies.
In the decade since St John opened, Henderson has opened just one more restaurant, Bread and Wine, also in east London.
Parkinson's disease, which caused uncontrolled movement in his arms, has forced him out of the kitchen. But pioneering therapy in which electrodes were planted in his brain has reduced his symptoms. He has a second cookbook out and says he is contemplating new restaurant projects.
Q: Were you surprised that the restaurant became so popular and has inspired such a devoted following?
A: "I am very happy. When we opened, opening a rather dour white restaurant, serving mainly offal, isn't exactly an instant recipe for success you fear. We had to endure a whole series of puns in reviews. Oh, 'you're offal but we like you' and 'offally nice'. Things have improved: there are less puns now. So the restaurant has grown up beyond the pun."
Q: Have you thought of opening a restaurant in the United States? New York? Or another restaurant in London?
A: "I'm not sure my wife and kids would be fairly happy if I was shooting off to New York to oversee, but you know, you never know. It has its tempting side. We don't move very fast. It took us nine years to open Bread and Wine, and I think that's keeping us quite happy at the moment."
Q: How did you come up with the idea of "nose to tail eating."
A:"The strange thing is that it wasn't like a gimmick or a theme. That's definitely the worst approach to food. It always just seemed sort of common sense to me to use the whole beast. Once you've knocked it on the head it's only common courtesy to eat it all. But also, it's not just thrift. Innards and extremities are delicious. The gastronomic possibilities of a pig are way beyond the pork chop or roast pork. Nature writes the menu for you, really. It's the middle of the game season, which is the most fantastic. It starts with grouse, goes into partridge and pheasant and woodcock. That's your autumn sorted. Falling from the sky... delicious things."