This is an article for the Western Mail magazine
The journey taken by e-cigarettes over the last few years has been remarkable.
From virtually nowhere, we can now find a shop selling them on every high street.
Tens of thousands of people suffer and die prematurely each year in the UK from cancer, heart disease and other conditions directly linked to smoking.
It is an addiction than many find difficulty in quitting.
E-cigarettes are not harmless nor are they risk-free, very few things are, but they do offer a route to a healthier lifestyle.
An expert independent evidence review published by Public Health England concluded that e-cigarettes are significantly less harmful to health than tobacco and have the potential to help smokers quit smoking.
They said that the current best estimate is that e-cigarettes are around 95% less harmful than smoking.
However, there are some who take a different view and who are cautious about the growth of this phenomena.
The Welsh Government started out by wanting to introduce the same restrictions on the use of e-cigarettes in public as apply to cigarettes.
They have now only want to limit the ban to some public spaces and buildings.
They are concerned that e-cigarettes will normalise smoking, especially for children.
They want to take a precautionary approach against the possibility that the vapour from e-cigarettes might be harmful.
What they are not doing is considering evidence of the good that e-cigarettes do and how their own actions might undermine that benefit.
They are rushing to legislation without having the done their homework so as to justify their ban.
When the smoking ban was introduced in Wales there was very clear evidence as to the harmful impact of second-hand smoke on people's health.
I sat on a cross-party committee that spend months looking at the research and listening to expert testimony before backing that ban.
There is no such evidence with regards to e-cigarettes.
Instead, ministers are using legislation to try to regulate a perfectly legal activity so as to change people's behaviour.
The anti-smoking campaign group ASH Wales, Cancer Research UK and Tenovus are among those opposed to this ban, whilst the British Heart Foundation, British Lung Foundation and the Royal College of Physicians want more evidence.
Furthermore in a public consultation on the proposals last year, 79% of responses were opposed.
Some people who vape are concerned that they will now be cast outside to join the smokers and that this will lead to them returning to smoking.
Indeed there is some evidence in other countries that this is what has happened.
There is strong evidence that e-cigarettes have enabled a large number of people to give up smoking, something that decades of lectures by government has failed to do.
The Public Health England review found that almost all of the 2.6 million adults using e-cigarettes in Great Britain are current or ex-smokers.
Most are using the devices to help them quit smoking or to prevent them going back to cigarettes.
As for the danger of normalising smoking or encouraging young people to take it up, other studies have found that this is not the case.
A survey by Action on Smoking and Health (ASH) Wales found very few young people between 13 and 18 who have never smoked have tried e-cigarettes.
Less than 3% of ‘never-smokers’ who responded to the survey reported having tried an e-cigarette.
The survey also suggested that, of the young people who had tried e-cigarettes, a quarter had done so to help them stop smoking or cut down on the number of cigarettes they smoked.
Professor Peter Hajek, the director of the Tobacco Dependence Research Unit at Queen Mary University of London, told a summit in Wales that “virtually nobody” who is a non-smoker experimenting with e-cigarettes would move on to daily smoking.
He said: “The concern that e-cigarettes would lure young people to smoking has not been supported by evidence.
“About half of non-smokers who experiment with cigarettes progress to daily smoking.
“In a striking contrast to this alarming effect, among non-smokers experimenting with e-cigarettes, virtually nobody progresses to daily use.”
Another survey, commissioned by the Welsh Government reported at the end of last year.
Researchers asked regular users of vaping devices if they had previously been tobacco users, and almost every single respondent said yes:
Of the 3,565 people aged 16 and older spoken to, only 1% of adults said they were e-cigarette users who had never smoked before.
A further 9% said they had tried e-cigarettes and considered themselves “non-smokers”.
Of those who currently use e-cigarettes, not one person said they had never smoked before.
Both Cancer Research UK and ASH Wales have warned that the e-cigarette ban could be a backwards step in the fight to reduce smoking rates.
In addition the saving to the public purse of the growth of e-cigarettes is substantial, and that is before we consider the improved health of ex-smokers.
The Health and Social Care Information Centre state that the average cost to the taxpayer of helping a smoker quit using Nicotine Replacement Therapy products rather than e-cigarettes is between £150 and £300.
Many people need more than one treatment and many revert back to smoking after some time.
There are roughly 467,530 smokers in Wales (20 per cent of the adult population).
If each of those quit smoking via vaping instead of using taxpayer funded Nicotine Replacement Therapy products, then the saving to the Welsh health budget could be over £10.5m.
Good legislation is evidence-based and will seek to right a wrong or improve the quality of our lives.
Proposals by Welsh Ministers to restrict the use of e-cigarettes in some public places fails to meet either of those tests.
It is not the role of Government to tell people how to conduct their lives without good quality evidence of harm to support their actions.