In 1964, when I was a medical student, Birmingham City Council decided to fluoridate its water supply. Over the weekend that the fluoride was supposed to be added, the Sunday Mirror carried many letters from people who could taste the difference and felt a variety of symptoms. On Monday the Medical Office of Health announced that a technical hitch meant that the fluoride would not in fact be added for another month. There were no further protests.

Thirty years later I was regional director of public health for the West Midlands (which includes Birmingham). From time to time the issue of fluoridation was raised, most often as some sort of scare about cancer, bone fractures, dental fluorosis, or allergies. A little over half of the region was fluoridated, and we knew in some detail which areas had fluoridated water and which did not. We examined every claim made against fluoride, and like most of the international public health agencies we were never able to find any evidence of the various allegations of harm. We even found that the incidence of some cancers seemed to be less in fluoridated areas, although such results may be …