SCHOOL pupils are using e-cigarettes as a gateway to smoking, according to a new study which raises concern over the "misleading promotion" of the products.

The research also found that most high school students find the fruity, sweet-like flavourings of e-cigarette liquids attractive.

It was suggested that some pupils use e-cigarettes to dupe their parents, who would otherwise smell tobacco on their clothes.

Others told researchers that they had seen fellow pupils openly selling and smoking e-cigarettes in class.

The study was led by researchers from Edinburgh and Stirling University, and published by the Royal Society for Public Health.

The team - led by Dr Marisa de Andrade - interviewed 182 13-to-16 year-old students from seven schools across Fife.

The study said: "In one school, it was suggested that up to 30 students used e-cigarettes and some then went on to use cigarettes."

Pupils from the school told researchers: "I think that's why most people go on from e-cigarettes to actual cigarettes, just to see what it's like, the actual ones, and then they get addicted to it."

Another added that e-cigarette users "might not feel like they're getting anything from the e-cigs, like a kick from it, they might get a better kick from a fag".

Others told of the growing popularity of vaping, with one saying: "At one point I just saw everyone walking around with them ... we all had one."

Another teenager from the same school told the researchers "people in the school were selling them" and a pupil had been seen smoking in class.

They said: "I thought it was a pen until I saw the smoke coming out of his mouth in English."

Several of the students also told researchers that e-cigarettes are more acceptable than regular cigarettes as they do not "leave a trace of smell".

One said: "Your parents won't know either because if you're out with friends and they're all smoking and that, and you decide you want to have one then they'll smell it on you.

"But if you have an e-fag then they can't smell it on you at all."

In the course of their research the academics also found that many of the students compared e-cigarettes with sweets.

One pupil said that vaping device itself "looks like sweets" as others told them "I just wanted to try it because it was, like, a fruity flavour."

Another described the smoke of e-cigarettes as "a powdery flavoured thing ... almost like a sherbert" as others said that - like sweets - the e-cigarette fluids are "really cheap" and readily available in newsagents and corner shops.

One said: "I work in a shop and at the till area ... there is a massive line, it's like a metre long, of different flavours. There is blueberries, bananas , Red Bull, Lucozade flavours, apple."

The study concludes: "Much more needs to be done to protect children from misleading messaging and promotion."

Sheila Duffy, chief executive of Action on Smoking and Health (ASH) Scotland, said: "E-cigarettes are less harmful than tobacco but are not completely safe and we believe there should be restrictions on advertising that targets children."

Public Health Minister Maureen Watt said: "The Scottish Government agrees that electronic cigarettes need appropriate regulation.

"While we accept that the devices may potentially help people smoke fewer cigarettes, or even stop altogether, we recognise that there are also risks involved.

"We have included a range of provisions to regulate the sale of these products in the Health Bill which is being considered by the Scottish Parliament at the moment.

"It contains measures to regulate e-cigarettes including age restrictions, proxy purchase, marketing restrictions and the creation of an e-cigarette retailers register."

She added: "Local authorities are responsible for ensuring schools are health promoting."