The latest heatwave reminded me of my brief career as a marijuana farmer. This wasn’t in the summer of 1976, when I was 13, but three years later, by which time my family had moved to Devon. My father had been commissioned to write the biography of Leonard and Dorothy Elmhirst, the founders of Dartington Hall, a utopian community in South Devon, and wanted to be nearer the archives and the couples’ friends and colleagues whom he was planning to interview.