A recent Columbia University study said it was a possibility e-cigarettes could act as a gateway to the non-electronic version and even to drugs such as cocaine. Action on Smoking and Health (ASH) estimate that there are 2.1m people in Great Britain currently using e-cigarettes.

The report states that the long-term health effects have not yet been established but doctors have said switching from tobacco to e-cigarettes could save 50,000 lives.

Is that growth in part driven by people who have never smoked trying it out to see if they like the feeling?

No. Not at all. Only 0.14% of non-smokers use e-cigarettes compared to 11.8% of smokers and 4.8% of ex-smokers in Great Britain, according to a new report by the Office for National Statistics (ONS). As the report puts it "e-cigarettes are used almost exclusively by smokers and ex-smokers."

These results back up the findings of a YouGov Survey commissioned by ASH. That survey showed that half of those using e-cigarettes viewed it as a way to transition off smoking completely. One in five said they were using the electronic version as they perceived it as less harmful than traditional cigarettes.

Over the last 40 years smoking has declined substantially. In 1973, the number of people who smoked regularly outnumbered those who had never done so. Now the majority of adults in Great Britain have never been smokers.