The government is set to crack down on sales of electronic cigarettes with tests being carried out to assess their levels of toxicity.
Many pubs and bars sell the products - which release a nicotine vapour - as a way around the smoking ban but health chiefs are concerned they do not comply with safety standards.
A Department of Health spokesman told The Publican: "Our scientific research has found that none of the products tested to date comply with product safety regulations.
"Local authorities enforce the law and the government is now working with them to crack down on e-cigarettes that contain toxic levels of nicotine, ensuring they are labelled and sold appropriately."
While an outright ban is not on the cards, trading standards officers are working with importers to ensure products on sale carry the right health warnings and some have already been suspended from the marketplace.
These products have raised a whole range of safety issues," said Jane MacGregor, advisor to the Local Government Association. She warned pubs and bars to check their supplies are correctly labelled and to ask suppliers for a test certificate. "It is a retailer's responsibility to make sure what they're selling is safe," she said
The probe follows a US government health alert on e-cigarettes warning two brands tested contained "carcinogens and toxic chemicals".
But firms marketing e-cigarettes to the UK licensed trade rejected the allegations.
Michael Ryan of E-Lites insisted that e-cigarettes provide "a much healthier alternative to tobacco cigarettes" and are only "marketed to existing smokers over 18 years".
He said: "The scope of the American analysis was very limited and relates to one brand not representative of the leading brands in the UK. It is out belief that using E-Lites as opposed to regular cigarettes is a life-saving choice."
Raff Bieniek, general manager of freehouse The Salusbury in Queens Park, West London, sells three or four E-Lite kits a week.
"The most important thing for us is that it means customers can smoke inside. We still don't allow it in the restaurant but they do smoke in the bar. And it's good for their health too.
But other licensees, including Tina Saxon of music venue the Haygate in Wellington, Shropshire, have stopped selling e-cigarettes after hearing "they may not be as healthy as people think".