More than half of the county's vapers have given up smoking after switching to e-cigs, a survey has found.
The study, conducted by YouGov on behalf of Action on Smoking and Health (ASH), shows an estimated 2.9 million adults in Great Britain currently use electronic cigarettes.
For the first time ever, the survey has found that more people (1.5 million) are using e-cigarettes instead of smoking.
They also said that the main reason of switching to e-cigarettes was to stop smoking.
ASH said that, while the news was positive, there were still many people who “dual-use” combustible and electronic cigarettes which still exposes them to the toxic, cancer causing substances in tobacco smoke.
Professor Ann McNeill, Professor of Tobacco Addiction at King’s College London, said: “This year’s ASH survey finds that around 1.5 million vapers are ex-smokers, for the first time a larger number than those who continue to smoke.
"This is encouraging news as we know that vapers who continue to smoke continue to be exposed to cancer-causing substances.
"The message for the 1.3 million vapers who still smoke is that they need to go further and switch completely.”
The number of vapers has increased fourfold since 2012, when the figure was 700,00, but growth has slowed in the last couple of years with fewer smokers understanding the reduced risk of vaping.
Deborah Arnott, Chief Executive of ASH, said: “It’s excellent news that the number of vapers who have quit smoking is continuing to grow, but there are still 9 million smokers compared to only 1.5 million vapers who don’t smoke at all.
“The rapid growth in e-cigarette use has come to an end while over a third of smokers have still never tried e-cigarettes, saying the main reasons are concerns about the safety and addictiveness of e-cigarettes.
"It’s very important smokers realise that vaping is much, much less harmful than smoking.”
The survey found that 13 per cent of respondents recognise that e-cigarettes are a lot less harmful than smoking, with 26 per cent thinking they are more or equally harmful.