Doctors should prescribe e-cigarettes to smokers: UK experts

The study commissioned by health authority Public Health England (PHE) found that so-called "vaping" electronic cigarettes was 95 percent less dangerous than smoking traditional tobacco cigarettes.

The battery-powered devices, which simulate the feeling of smoking but with nicotine inhaled in a vapour, could be a "game changer in public health", according to study co-author Professor Ann McNeill of King's College London.

Smoking is the leading cause of preventable deaths in England, accounting for over 80,000 a year, according to the National Health Service. Just under one in five of Britain's population smoke.

"Smoking remains England's number one killer and the best thing a smoker can do is to quit completely," said Professor Kevin Fenton, director of health and well-being at PHE.

"E-cigarettes are not completely risk-free but when compared to smoking, evidence shows they carry just a fraction of the harm."

Vaping is less common than traditional smoking, with an estimated 2.6 million people in Britain using electronic cigarettes.

Currently, none of the devices are licensed for medicinal purposes in Britain, meaning doctors cannot recommend them to patients.

But the study found that contrary to public perceptions, e-cigarettes did not endanger health in the same way as traditional tobacco cigarettes.

"My reading of the evidence is that smokers who switch to vaping remove almost all the risks smoking poses to their health," said Professor Peter Hajek of Queen Mary University, another co-author.

The experts also said that there was no evidence so far that e-cigarettes were a route into smoking for children or non-smokers.