An independent review for Public Health England has found that e-cigarettes are 95 per cent less harmful than tobacco and should be prescribed on the NHS.
The reports writers say vaping - the term for smoking e-cigarettes - could be a "game changer" for persuading people to give up the real thing. They also claim there is no evidence that e-cigarettes act as a gateway that encourages children to start smoking.
The Welsh government has previously announced that it plans to ban the use of e-cigarettes in enclosed spaces. They are increasingly popular and are now used by 2.6 million adults in Britain.
There are no claims that they are entirely free from health risks, but the evidence suggests they cause far less harm than normal cigarettes. Despite this, public health experts can't agree on whether they should be seen as a much safer alternative to smoking, or a pathway to a deadly addiction. The British Medical Association has expressed caution, although many health campaigners have welcomed the findings.
Public Health England says the results of the study are abundantly clear. On the question of safety they estimate that e-cigarettes are "around 95% less harmful" than smoking.
One of the reports authors, Prof Ann McNeill from King's College London, said e-cigarettes could be a "game-changer" in public health.
"At the moment, 80,000 people in England die every year as a result of cigarette smoking. If everybody who was smoking switched to e-cigarettes that would reduce to about 4,000 deaths a year. That's the best estimate at the moment. It may well be much, much lower than that."
The report says that although GPs and stop smoking services are currently not able to prescribe e-cigarettes as none of the products on the market are licensed for medicinal purposes, they hope that hurdle will be removed in the future.