E-cigs to be classed as medicines under new proposals

The move will also mean that licensed e-cigarettes can be prescribed by medics to help smokers cut down or quit.

It is estimated that 1.3 million people across the UK use battery-powered e-cigarettes, which can look like real cigarettes but users inhale a mist of nicotine instead of smoke.

When the user sucks on the e-cigarette, liquid nicotine is vapourised and absorbed through the mouth. When they breathe out, a plume of what appears to be smoke is emitted but it is actually largely water vapour.

In the past, experts have said that if all smokers were to use e-cigarettes instead of normal cigarettes, millions of lives could be saved, because they do not contain harmful tar like in real cigarettes.

But others have raised concerns about safety and regulation of the products.

Experts said that users could not be certain about the purity of the nicotine contained inside. MHRA research found that nicotine levels can be "considerably different" from the level stated on the label.

And the amount of nicotine per product was found to differ from batch to batch - which casts doubt on how useful the products are to people who want to cut down or to stop smoking, a spokesman said.

Now the MHRA will regulate the products so there is a consistent standard across all licensed products sold over the counter.

While the regulator is not planning to recall unlicensed e-cigarettes - saying that the benefit outweighs the risk of users turning to real cigarettes - it is hoped that in the long term all products will be licensed.

The MHRA's group manager of vigilance and risk management of medicines, Jeremy Mean said: "Our research has shown that existing electronic cigarettes and other nicotine containing products on the market are not good enough to meet this public health priority.

"Some nicotine containing products are already licensed and the Government's decision to work towards medicines licensing for all these products is designed to deliver quality products that will support smokers to cut down and to quit.

"The decision announced today provides a framework that will enable good quality products to be widely available. It's not about banning products that some people find useful, it's about making sure that smokers have an effective alternative that they can rely on to meet their needs."

The UK Government's Chief Medical Officer Professor Dame Sally Davies said: "Smokers are harmed by the deadly tar and toxins in tobacco smoke, not the nicotine.

"While it's best to quit completely, I realise that not every smoker can and it is much better to get nicotine from safer sources such as nicotine replacement therapy.

"More and more people are using e-cigarettes, so it's only right these products are properly regulated to be safe and work effectively."

Deborah Arnott, chief executive of health charity Action on Smoking and Health, said: "Regulation will ensure that e-cigarettes meet the same standards for quality, safety and efficacy as medicines while remaining as readily available to smokers as they are today.

"Crucially it will also ensure marketing of e-cigarettes and other such products is controlled to prevent their promotion to children and non-smokers."

Clare Gerada, chairwoman of the Royal College of General Practitioners, said: "Rates of smoking in the poorest in our communities remain high, and as a GP in a deprived area of London I see first hand the deaths and disease this causes.

"The RCGP supports MHRA regulation of novel nicotine products such as e-cigarettes as this will ensure that they are of good quality and reliability and are effective in helping smokers who want to use them to cut down and quit."

Penny Woods, chief executive of the British Lung Foundation, said: "With over 100,000 people dying annually from smoking-related diseases, it is clear that the harm-reduction, even life-saving potential of e-cigarettes as an alternative to smoking could be immense.

"The industry regulation announced today is an important step towards realising that potential, whilst also working to prevent nicotine products being sold to children."

Vivienne Nathanson, director of professional activities at the British Medicial Association, said: "It's really important that we find out if the hand to mouth use of e-cigarettes either breaks or reinforces smoking behaviours. We need to know if e-cigarettes actually help smokers quit."

But manufacturers expressed concern about the "unjustified" medical regulation.

Damien Scott, commercial manager of company SKYCIG, said: "E-cigarettes are currently self-regulated by the Electronic Cigarette Industry Trade Association to ensure they meet consumer standards.

"And, although regulatory support in these endeavours would be fully welcomed by the industry, medical regulation which could restrict access to these lifestyle products is entirely unjustified, particularly given the possibility of these smoking alternatives to potentially save millions of lives."

James Dunworth, co-founder of EcigaretteDirect.co.uk, said: "Electronic cigarettes are currently regulated. What we need is not more regulations, but an enforcement of existing ones.

"Our eliquid is produced from pharmaceutical grade nicotine in laboratory conditions, and has been tested in a UK government approved lab."

Professor Kevin Fenton, director of health and wellbeing at Public Health England, said: "Licensing of nicotine containing products is an important step in managing the risk of poor and ineffective products, maximising the potential for public health gain and eliminating the opportunity to advertise these products to children or non-users of tobacco products."