Millions of lives could be saved around the world if all smokers made the switch from tobacco products to e-cigarettes, it has been claimed.
Speaking at the 2013 E-Cigarette Summit at London's Royal Society, University College London's Professor Robert West said the devices could cut the number of smoking-related diseases significantly, therefore reducing death rates.
'I think it can be achieved but that's a hope, a promise, not a reality,' he added.
According to Action on Smoking and Health, around 700,000 people in the UK already use e-cigarettes, which vaporise liquid nicotine for them to inhale.
However, it was revealed last month that they may be labelled as medicinal products in the future, as members of the European parliament are considering a proposed update of the laws governing them.
They will take a vote soon, but it may be that the change comes into effect as early as next year.
Read more about the summit here