Somewhere out in cyberspace, half a dozen strangers are having a chat on a medical website. It’s a slow process, somewhat akin to playing chess using second-class post. But the discussion - about why teenagers smoke - makes particularly interesting reading, since the participants are all teenagers.

“I believe kids smoke because they figure they can stop before they actually get the effects that they are warned of,” says one. “It’s because their parents smoke,” says another. And someone else says that the very opposite is the case. “From personal experience,” he says, “I have found that my friends smoke because their parents would not approve of it.”

One boy believes it is to do with low self-esteem. “Kids do anything to fit in so they don’t get picked on, such as trying to be a class clown, not doing homework, not communicating with parents, and acting tough. When they try all those things and still don’t fit in, they smoke.”

It’s not in the nature of these Internet discussions to arrive at a conclusion, and this one is no exception. But two things are clear. This is a complex issue, and there is no simple solution to the problem.

And a problem it most certainly is. In 1997, the Department of Health estimated that children who smoked were spending pound;100 million a year on their habit - an average of pound;13 a month each. The following year, the Schools Health Education Unit revealed that around one third of girls aged 14-15 smoke, a rise of about half since the late Eighties.

According to Amanda Sandford, research manager with Action on Smoking amp; Health (Ash), 10-12 per cent of children in Britain are regular smokers before the age of 16. And while boys seem to be getting the health message, the number of girls smoking - particularly Year 10 girls - has been creeping up.

And somewhat depressingly for health educators, smoking levels among under-18s have increased rather than decreased since the Government published its Health of the Nation targets in 1992.

All the evidence suggests that it is this influx of children replacing the adults who either die or quit the habit that is keeping the number of smokers in Britain static. “Given all we know about the dangers of smoking, this is quite a worry,” says Sandford.

“Lots of research has been done into the effectiveness of health education,” she says. “The best we can say is that it’s likely to delay the onset of smoking. But although those who get the education about the dangers at 11 or 12 may start when they are 14 or 15, it’s still worthwhile, because the earlier they start, the more likely they are to get health problems later in life. This seems particularly true with lung cancer.”

Ash is developing a resource for schools that will enable teachers to incorporate smoking education into the wider curriculum. “It would take into account the social and economic consequences of smoking,” says Sandford. “For example, in a maths lesson, you could work out the cost of smoking to the health service.”

She believes this may be more effective than focusing purely on the health message. For while it’s clear that most young smokers are now aware of the dangers (figures published in February by the Office of National Statistics show that 99 per cent of children accept that smoking can cause lung cancer), it’s less clear whether the bare facts mean much to them.

“Kids may not take on board the health message about smoking because it takes so long for the effects to become apparent,” says Sandford. “They know that if they drink too much, they’ll get drunk and be very ill. But if they smoke, they’ll feel fine the next day, and the idea of getting cancer and heart disease in their forties is something they just can’t relate to.”

Given these difficulties, Sandford believes that more needs to be done to prevent children getting hold of cigarettes, since accessibility can make the difference between smoking and not smoking. “Children with parents or older siblings who smoke are twice as likely to smoke themselves, because they’re there in the house and easy to get hold of,” she says.

And while those who continue might initially have to persuade older children to buy cigarettes for them, they will soon find it easy enough to buy cigarettes from vending machines, corner shops or garage forecourts.

“Something like 80 per cent of smokers start before the age of 18,” says Sandford. “No one has yet found a way of deterring them and, given that it’s a legal drug, I’m not sure we ever will, unless really strong efforts are made to restrict sales.”

She would like tobacco retailers to be licensed, in the way that premises selling alcohol are licensed at the moment. “Then if a retailer is found to be selling to children, the licence could be revoked.”

However, Sandford has mixed feelings about identity card schemes which she believes could add to the glamour of smoking by giving the habit “adults only” status. “We think this is the cynical motive of tobacco companies who profess to be concerned about youth smoking and say they think the legal age of buying cigarettes should be raised from 16 to 18,” she says.

Professor Anne Charlton, who has spent years studying child smoking for the Cancer Research Campaign, believes that health education is virtually powerless in the face of fashion and group dynamics.

“For a start, I would never call it peer pressure,” she says, “because I don’t think there are many big bad smokers pushing kids into smoking. But I believe in peer bonding. Children want to belong to a group that they consider to be the top group. If that group smokes, then they will want to take it up.”

Fashion, she says, is a strong influence, which goes some way to explaining why so many girls smoke. “If you talk to girls aged 15 to 17, it’s very clear that smoking is to do with their image - their image of themselves and the image they project to other people. If you smoke certain kinds of cigarette, you are a certain kind of person. The main thing is to have the right packet.”

She is adamant that the effects of advertising, even in its currently depersonalised form, can be clearly seen in the attitudes of children to cigarette brands. “For example, we have found that 12-year-old boys who watch motor racing on television are twice as likely to become regular smokers in the next year,” she says.

“People say, ‘Oh, warn them about the health risks and they won’t do it’. No, no, no. That has nothing to do with it. It’s all to do with image and the group you want to belong to.”

Charlton believes that teaching a child how to say “no” to cigarettes is pointless if the child wants to say “yes”. Rather, she favours lessons that make children aware of how marketing works and the ways in which they are being manipulated by the tobacco industry. Her fear, though, is that even these tactics are at the mercy of powerful social forces.

“As smoking begins in each country,” she says, “it’s the men who take it up first. It rises rapidly, hits a plateau and then it falls. The men are then followed by the boys, then by the women and finally by the girls, in a series of overlapping curves.

“India, for example, is in a very early phase of that. The men have gone quite high and the boys are still quite low and the women have only just got to the bottom of the rising curve. In the UK, we’ve gone right past the plateau of the men, boys and women. The boys and men have gone down very steeply, the women are just past the plateau and are going down more slowly, and the girls haven’t yet reached the end of the plateau.”

Unfortunately, she says, there’s a danger that when the majority cease an activity, group leaders take it up again - “to be different” - and it once again becomes fashionable.

“I’ve been a great supporter of teaching about various aspects of smoking in schools for many years,” says Charlton, “but I sometimes wonder if we’ll get anywhere. While cigarettes are still there and sold and advertised, we’re flogging a dead horse.

“I don’t say that we shouldn’t do anything in schools, but it’s got to be part of a holistic programme - a national, integrated programme rather than something that just focuses on the kids. Until we do that, the figures will go down, but then they’ll come up again.”