In these pages, and in my last book, I’ve written about the lessons we should learn from Richard Doll and Austin Bradford Hill’s investigations in the 1950s into the link between cigarettes and lung cancer. There is one lesson I failed to draw.

I wrote that in 1954 the British epidemiologists Doll and Hill “marshalled some of the first compelling evidence that smoking cigarettes dramatically increases the risk of lung cancer”. That is not untrue, but neither is it the whole truth.

Two pathologists, Eberhard Schairer and Erich Schöniger, published a study of “lung cancer and tobacco consumption” well before Doll and Hill took up the question. Schairer and Schöniger began by noting that lung cancer, a rare disease in the 19th century, had shown a “pronounced increase”, and then dismissed the plausible-seeming idea that the cause was vehicle exhausts. Lung cancer was on the rise in rural areas just as much as urban, they noted, adding that “the male gender is much more frequently afflicted . . . than the female,” yet “both genders are exposed to almost the same degree” to exhaust fumes.