Smokers who use e-cigarettes to quit are more likely to succeed than those who use willpower alone or buy nicotine replacement therapies, such as patches or gum, a study suggests. The survey of nearly 6,000 smokers found a fifth had quit with the aid of e-cigarettes. That was 60% higher than those who did not use the devices, the study said. The University College London team said they were "cautiously positive" about the role e-cigarettes could play. E-cigarette use has shot up in recent years. Action on Smoking and Health estimate there are more than 2m people using them - triple the number from two years ago. Half of smokers have tried them compared to 8% in 2010. Users experience the sensation of smoking by inhaling a vapour which contains a concentration of nicotine. (click for more)