E-cigarettes 'help smokers to quit'
20 May 2014 Last updated at 13:40 BST
Smokers who use e-cigarettes to quit are more likely to succeed than those who use willpower alone or buy nicotine replacement therapies, 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.
Branwen Jeffreys reports.