Explosive growth in the use of e-cigarettes in the U.K. is perhaps the latest sign of changing consumer habits in an era marked by gadgets and technology.
Earlier this week, the country's statistics office said that it was adding e-cigarettes to the basket of goods and services used to calculate inflation at the consumer level. Headphones and music streaming service, Spotify, were also added to the list.
"This is very much reflective of how much the category (e-cigarettes) has boomed in recent years, with our predictions showing the market to have risen in value by 340 percent in 2013 and a further 4 percent in 2014," Roshida Khanom, senior personal care analyst at market research firm Mintel told CNBC.
According to a U.K. public health paper published last year, the e-cigarette market was worth £193 million in 2013 and is expected to be worth £340 million in 2015. Globally, the market is expected to be worth $3.5 billion in 2015, according to Bonnie Herzog, Wells Fargo Securities' senior tobacco and beverage analyst.
"E-cigarettes initially were limited to online channels, however growing availability is increasing consumer accessibility," said Mintel's Khanom. "In 2014 alone, e-cigarettes became available in newsagents, supermarkets as well as specialised stores. As such, the segment is likely to show continued growth."
E-cigarettes take the form of a battery operated device that aims to stimulate cigarettes.
While the risks of e-cigarettes are intensely debated, they are generally viewed as a safer alternative to cigarettes. Although they deliver a nicotine-laced vapour to smokers they do not contain the harmful chemicals contained in tobacco.
This may help explain the popularity of e-cigarettes, experts said.
"About two-thirds of smokers say that they want to give up smoking, but they continue because they are addicted to the nicotine and so find it hard to quit," Amanda Sandford, research manager at Action on Smoking and Health (ASH), a public health charity, told CNBC.
"These products provide the nicotine that smokers crave but in a safer way, so they are not getting all the harms from the tobacco smoke and that seems to suit a lot of people."
Evidence suggests that the e-cigarette market, while still a small fraction of the overall cigarette market, is gaining ground in the U.S. and Europe, with many big tobacco firms moving into the segment in recent years. For instance, British American Tobacco, one of the world's biggest tobacco firms with brands such Lucky Strike, sells an e-cigarette called Vype.
However, Sandford at ASH said it was unclear whether the growth in the e-cigarette market would be sustained.
Khanom said that Mintel's research showed that e-cigarettes had become a key shopping trend among smokers, although non-smokers were not using e-cigarettes.
"I started smoking them to try and reduce my consumption of real cigarettes," Fabien Polair, a marketing director living in London, who briefly used e-cigarettes told CNBC. However, he said the trend appeal of smoking e-cigarettes was low.
"The first time you smoke an e-cigarette in public you feel quite ridiculous and you're trying to hide it," he said. "I think that's one of the reasons most smokers don't even want to try them. To me, people smoking them are genuinely trying to stop smoking real cigarettes."
-- CNBC's Kate Rogers contributed to this report.
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