E-cigarettes are estimated to have helped 16,000-22,000 smokers in England to quit in 2014

The UCL team has been tracking the rapid rise in use of e-cigarettes using monthly national surveys and estimates that in 2014 almost 900,000 smokers used one of these products to try to quit.

Previous research has found that when used in this way, e-cigarettes increase the chances of success by around 50% compared with using no support or one of the traditional nicotine products such as gum or skin patch bought from a shop.2,3 This raises the long-term success rates from around 5% to around 7½%. The increased success rate amounts to an additional 22K people stopping who would otherwise have continued smoking. Some of these people may have used an e-cigarette instead of one of the more established aids to cessation such as the Stop-Smoking Services. Adjusting for this, the number helped by e-cigarettes may be somewhat lower, at 16K.

Professor Robert West, who led the research team, said "E-cigarettes appear to be helping a significant number of smokers to stop who would not have done otherwise -- not as many as some e-cigarette enthusiasts claim, but a substantial number nonetheless."

Professor West added, "There have been claims by some public health researchers that e-cigarettes undermine quitting if smokers use them just to cut down, and that they act as a gateway into smoking. These claims stem from a misunderstanding of what the evidence can tell us at this stage, but this is clearly something we need to watch carefully."