The report said there was “much public misunderstanding” about nicotine, with fewer than 10 percent of adults understanding that the vast majority of the harms from smoking are not caused by nicotine.

It said the evidence does not support concerns that e-cigarettes are a gateway into tobacco smoking among young people.

“Our new review reinforces the finding that vaping is a fraction of the risk of smoking, at least 95 percent less harmful, and of negligible risk to bystanders,” said John Newton, a professor and director for health improvement at PHE.

“It would be tragic if thousands of smokers who could quit with the help of an e-cigarette are being put off due to false fears about their safety.”

The PHE report comes a few weeks after a U.S. National Academies of Sciences, Engineering and Medicine report on e-cigarettes. Summarizing data from hundreds of scientific studies, that report also said e-cigarettes are likely to be far less harmful than regular tobacco cigarettes.

PHE called on smokers and health authorities to act now on the evidence reviewed in these latest reports.

Any smoker who has struggled to quit should try switching to an e-cigarette and get professional help, it said, adding: “The greatest quit success is among those who combine using an e-cigarette with support from a local stop smoking service.”

It also called on Britain’s National Health Service to ensure e-cigarettes are available in hospital shops along with other nicotine replacement products such as gum and lozenges.

The UK campaign group Action on Smoking and Health welcomed the report, saying it was part of a growing scientific consensus that e-cigarettes are much less harmful than tobacco.