The hope many smokers have of being able to enjoy their habit without restrictions might go up in smoke as the World Health Organisation (WHO) calls for a ban on e-cigarettes indoors. The organisation believes this alternative to conventional cigarettes might not be safe for secondary smokers, as e-cigarettes could increase the levels of some toxins and nicotine in the air.
?
E-cigarettes work by heating liquid nicotine - the substance in tobacco which makes it addictive - and turning it into vapour, which is breathed in by the smoker. Since there's no smoke, puffing on e-cigarettes is being called 'vaping'.
?
According to estimates, the number of e-cigarette users in the UK alone has tripled over two years to more than 2 million, in a market worth more than £90m a year.
?
Many think e-cigarettes let smokers avoid legislation put in place about seven years ago to protect staff in the workplace. Vaping bars have sprung up in London, but their future remains uncertain. A growing concern about public health has led many pubs, train companies and offices to ban the use of these devices.
?
The British Medical Association is joining the WHO in asking for restrictions on e-cigarettes. They fear marketing them as fashion accessories or medical aids might undo their campaign against smoking. Ram Mooray from the organisation, said: "Our biggest concern is that smoking becomes glamorous again."
?
So, do the disadvantages of e-cigarettes outweigh the benefits? The debate is likely to heat up. Research by University College London says that for every million smokers who switch to e-cigarettes, more than 6,000 lives a year could be saved. Some smokers are using them to reduce their craving for cigarettes.
?
Professor Peter Hayek, Director of the Tobacco Dependence Research Unit at Queen Mary University of London, warns against restricting e-cigarettes. He says it's "like asking people to stop using mobile phones and tablets because of a one-in-10-million chance that the battery might overheat in your device."