Smokers who visit accident and emergency departments are being given e-cigarette "starter packs" to help them quit as part of a new trial.
The study, which aims to recruit around 1,000 patients, will run over 30 months across five hospitals in England and Scotland and will see smokers given quitting advice along with the e-cig kit.
It follows new research by the University of Oxford which showed that nicotine electronic cigarettes could increase the number of people who stop smoking compared to nicotine replacement therapy - such as chewing gum and patches - and electronic cigarettes that do not contain nicotine.
Professor Caitlin Notley, from the University of East Anglia's Norwich Medical School, which is leading the study, said: "Many people who smoke want to quit, but find it difficult to succeed in the long term.
"Electronic cigarettes mimic the experience of cigarette smoking because they are hand-held and generate a smoke-like vapour when used. They can be an attractive option for helping people switch from smoking, even if they have tried and failed in the past.
"We know that they are much less harmful than smoking tobacco, and that they have been shown to help smokers quit."
The new trial will offer e-cigarettes to patients attending A&E departments "for any reason" to try to encourage and support them to quit smoking - even for those who might not have considered it before.
The hospitals involved include Norfolk and Norwich University Hospital, the Royal London Hospital and Homerton University Hospital in London, Leicester Royal Infirmary and the Royal Infirmary of Edinburgh.
Commenting on the study, Suzanne Cass, CEO of ASH Wales, said the charity would welcome a similar scheme being introduced in Wales.
"We know e-cigarettes are a really effective quit smoking tool and health experts say vaping is around 95% less harmful than smoking tobacco," she said.
"Our advice is if you don't smoke, don't vape. However, for smokers, switching completely to e-cigarettes will significantly reduce the risks to your health.
"Smoking is the biggest avoidable cause of early death among adults in Wales, killing thousands of people every year. Providing smokers attending A&E departments with free e-cigarettes is a great way to encourage them to quit and we would welcome a similar scheme for Wales.
"The new smoking ban in Welsh hospitals offers an ideal opportunity to step-up efforts to support smokers to quit and offer them the help they need to deal with the symptoms of nicotine withdrawal."
Smokers who agree to take part will be randomly assigned to receive either smoking advice during their emergency department wait, an e-cigarette starter pack and referral to local stop smoking services, or just written information about locally available stop smoking services.
Both groups of patients will be asked if they are still smoking one, three and six months after they attended hospital.
Prof Notley said: "We'll be looking at the number of people who successfully quit smoking across both groups, to see which intervention works best. We'll also work out how much it would cost to roll the scheme out nationally," she added.
The new trial is funded by the National Institute for Health Research (NIHR) and will be run by the Norwich Clinical Trials Unit at UEA.
