Over 50 respected doctors and professors from around the world have said that tobacco harm reduction products such as e-cigarettes, ‘could be among the most significant health innovations of the 21st century', with the potential to save millions of lives.

In a letter to the World Health Organization (WHO), the 53 experts, many of whom work in the field of public health, insisted that the ‘urge to control and suppress' these products should be resisted.

E-cigarettes are battery-powered devices designed to supply nicotine through inhaled water vapour. They are currently at the centre of a major debate, with some people stating that they can help smokers to quit the habit and others insisting that they are potentially harmful to health.

As a result of potential health concerns, the HSE introduced a ban on e-cigarettes in all hospitals and health facilities from May 1. It said this ban 'followed a detailed review of their safety' and insisted that ‘there currently is no conclusive evidence that e-cigarettes are safe for long-term use, or are effective as a smoking cessation aid'.

However, the experts insist that such products have an important role to play in helping to reduce the health burden of smoking. They refer specifically to ‘tobacco harm reduction - the idea that the 1.3 billion people who currently smoke could do much less harm to their health if they consumed nicotine in low-risk, non-combustible form'.

"We have known for years that people 'smoke for the nicotine, but die from the smoke'. The vast majority of the death and disease attributable to tobacco arises from inhalation of tar particles and toxic gases drawn into the lungs. There are now rapid developments in nicotine-based products that can effectively substitute for cigarettes but with very low risks. These include e-cigarettes," the experts said.

They acknowledged that the idel scenario would be for people to quit smoking altogether, however, they pointed out that experience has shown that many smokers ‘cannot or choose not to give up nicotine and will continue to smoke'.

Their letter emphasises that tobacco harm reduction ‘is part of the solution, not part of the problem'.

"If regulators treat low-risk nicotine products as traditional tobacco products and seek to reduce their use without recognising their potential as low-risk alternatives to smoking, they are improperly defining them as part of the problem," the experts said.

They insisted that policies that are ‘excessively restrictive' on these products may have the unintended consequence of ‘protecting cigarettes from competition from less-hazardous alternatives'. This could cause harm as a result.

They also described it as ‘counterproductive' to ban the advertising of e-cigarettes and other similar products.

"The case for banning tobacco advertising rests on the great harm that smoking causes, but no such argument applies to e-cigarettes, which are far more likely to reduce harm by reducing smoking," they noted.

They also said that is ‘inappropriate to apply legislation designed to protect bystanders or workers from tobacco smoke to vapour products'.

"There is no evidence at present of material risk to health from vapour emitted from e-cigarettes. Decisions on whether it is permitted or banned in a particular space should rest with the owners or operators of public spaces," they said.

The experts believe that excessive taxation of these products could deter smokers from switching, which leads to more smoking and related harm. They also note that there is no ‘credible evidence' that these products act as a ‘gateway' to higher risk tobacco products.

They added that they are ‘deeply concerned' that the classification of these products as tobacco ‘will do more harm than good'.

The letter was written by doctors and professors from a number of countries including the UK, Sweden, Italy, the US, Canada and Australia. It was sent to Dr Margaret Chan, director general of the WHO.