'Tea is an addiction, but an addiction different from all others. It is milder, a habit relatively easily broken. It is more universal. Most unusually, it is good for the addict. And it is largely unnoticed both to those addicted and others. Indeed, the conquest of the world by tea has been so successful that we have forgotten that it has happened at all. Tea has become like water or air, something many of us take for granted.'

Professor Alan Macfarlane, 'Green Gold, The Empire of Tea'