Over the past few decades, the practice of buying and smoking cigarettes has been increasingly regulated across the western world. The value of such regulation is today beyond any doubt.

Smoking kills 100,000 people a year in Britain – and five million worldwide. Tobacco smoke contains 70 carcinogens that cause 90 per cent of lung cancer deaths and a third of other cancers. It induces heart disease, strokes, premature births, cataracts and a host of other avoidable complications. Exhaling affects non-smokers, especially children, who often cannot escape their parents’ habit.

However, the debate on cigarette regulation is now moving into a new arena, focused on so-called “e-cigarettes”. Advances in technology have made it possible to produce cheaply a battery-powered device that heats a liquid containing nicotine into a vapour that can then be smoked, or “vaped” much like a cigarette. E-cigarettes contain none of the carcinogens, such as tar and arsenic, involved in ordinary cigarettes.