London: The number of people in Britain who have tried e-cigarettes has almost doubled in just two years, says a new study. The researchers examined e-cigarette use -- and attitudes to the devices -- across Europe between 2012 and 2014. The paper, published in the journal Tobacco Control, found that the proportion of people in Britain who had tried an e-cigarette had increased from 8.9 per cent to 15.5 per cent. The average number of people across Europe who had tried an e-cigarette increased by 60 percent between 2012 and 2014, from 7.2 to 11.6 per cent. The research also showed the proportion of people across Europe who considered the devices dangerous had also nearly doubled, from 27 per cent to 51 per cent. E-cigarettes work by delivering nicotine into the lungs in the form of a vapour. The devices contain nicotine in a solution of either propylene glycol or glycerine and water, and sometimes flavourings. When a person sucks on the device, a sensor detects the air flow and heats the liquid inside the cartridge, causing it to evaporate. "This research shows e-cigarettes are becoming very popular across Europe -- with more than one in ten people in Europe now having tried one of the devices,” said lead author of the research Filippos Filippidis from Imperial College London. “However there is a debate about the risks and benefits associated with e-cigarettes. For instance we don't know whether we may start to see diseases emerge in 10-20 years' time associated with some of the ingredients,” Filippidis pointed out. The research, which used data from over 53,000 people across Europe (at least 1,000 people from each country), also revealed France had the highest use of e-cigarettes -- with one in five people saying they had tried the devices. "Although this data shows most of the people who use e-cigarettes are current or former smokers -- which suggests the devices may be helping some of them quit smoking -- it is worrying that some people who have never smoked are using them. This raises the question of whether they could be a 'gateway' to smoking conventional cigarettes," Filippidis added.