Since 2013, one person has switched from traditional smoking to so-called vaping every four minutes in the UK, according to new research from EY.
And now more than 2m British people vape, a total of 4.2 per cent of adults.
By contrast, the next highest penetration is in France, where just over 3 per cent use electronic products.
The perceived health benefits of electronic cigarettes are believed to be key to their take up, and the UK government's advisory body Public Health England and the Royal College of Physicians have been among the groups to suggest e-cigarettes could function as a safer equivalent to the traditional products.
Kingsley Wheaton, managing director for Next Generation Products, at British American Tobacco said: “The UK has one of the most progressive regulatory environments for e-cigarettes and that’s reflected in consumer uptake and category growth.
“The UK government has created an environment which enables consumers to be informed about the products, have access to them and allows manufacturers to innovate and provide quality vaping products.”
The total e-cigarette market worldwide is estimated to be worth £6.1bn, and is projected to reach £12bn by 2020.