Researchers from University College London (UCL) estimated that for every million smokers who switch from tobacco to electronic cigarettes, over 6,000 premature deaths would be prevented each year in the UK.
There are around nine million British smokers and if they all switched to the nicotine vapour inhalers instead of the tobacco products they use, around 54,000 lives could be saved.
The experts said the reduced mortality rate even accounts for the possibility that e-cigarettes may carry an increased risk of death.
But in an editorial published in the British Journal of General Practice, Professor Robert West and Dr Jamie Brown from UCL's Department of Epidemiology and Public Health argue that though some toxins are present in the vapour from e-cigarettes the concentrations are "very low".
"The vapour contains nothing like the concentrations of carcinogens and toxins as cigarette smoke," they wrote.
"In fact, toxin concentrations are almost all well below 1/20th that of cigarette smoke."
They also tried to dispel comments about e-cigarettes "re-normalising" smoking and the products acting as a "gateway" to smoking.
The rise in use of e-cigarettes has been accompanied by an increase in the numbers of smokers quitting and a continued fall in people smoking, they said.
Meanwhile the number of e-cigarette users who took up the habit having never smoked in the past is "extremely small".
They wrote: "There are a number of public health advocates who appear to consider electronic cigarettes (e-cigarettes) primarily as a threat to public health.
"Given that smokers smoke primarily for the nicotine but die primarily from the tar, one might imagine that e-cigarettes would be welcomed as a means to prevent the death and suffering caused by cigarettes."