Televised e-cigarette adverts that include vaping – which is classed as inhaling or just holding the product – could be enticing current smokers to pick up another cigarette and could even be doing the same for ex-smokers.

Research from the University of Pennsylvania's Annenberg School for Communication found ex- and current smokers are more likely to imbibe if they have viewed an e-cigarette advert.

Using standard tests to measure the urge, they found smokers were keen for a cigarette after viewing, and quitters were less confident that they could hold off after watching an advert that included vaping, as opposed to e-cigarette adverts which did not include it.

"We know that exposure to smoking cues such as visual depictions of cigarettes, ashtrays, matches, lighters, and smoke heightens smokers' urge to smoke a cigarette, and decreases former smokers' confidence in their ability to refrain from smoking a cigarette," Dr Maloney, lead co-author of the study, said.

"Because many e-cigarette brands that have a budget to advertise on television are visually similar to tobacco cigarettes, we wanted to see if similar effects can be attributed to e-cigarette advertising."

Maloney and Dr Joseph Capella garnered more than a dozen adverts on the internet and found 35% of the regular smokers who viewed an advert showed vaping reported having a tobacco cigarette during the study.

The duo wrote in Health Communication: "Given the sophistication of cigarette marketing in the past and the exponential increase in advertising dollars allotted to e-cigarette promotion in the past year, it should be expected that advertisements for these products created by big tobacco companies will maximise smoking cues in their advertisements, and if not regulated, individuals will be exposed to much more e-cigarette advertising on a daily basis."