Once upon a time, a crafty fag behind the bike sheds was the mark of a teenage rebel. But not any more, which is why the vast majority of British 15-year-olds will be singularly unbothered about becoming the last generation legally allowed to buy cigarettes. A princely 3% of them smoke, a habit now widely regarded as for old people. One in five girls that age, however, use candy-coloured, sweet-flavoured vapes. They’re cheaper, just as easily bought underage, and don’t make your hair smell horrible. So why persevere with raspy throats and ash on the carpet when they can get a nicotine fix that tastes of bubblegum or banana, from a device dinky enough to hide in a school blazer pocket? (The patronising old marketing advice to “shrink it and pink it” – create a handbag-sized, pastel version – if you want to sell to women could have been designed for the vape market, where young women now outnumber men; the reverse was true of tobacco.) There’s something both rebellious and oddly innocent-looking about vaping, a perennially appealing combination to teenage girls. They know smoking kills, but puffing on a strawberry e-cigarette seems barely more dangerous than sucking the end of your Hello Kitty pen in primary school, despite the worrying questions hanging over vaping’s unknown long-term effects and over high levels of toxic heavy metals in some cheap devices. When scientists tested a haul confiscated at one school in Kidderminster, Worcestershire, they found children using them could have been inhaling more than double the daily safe amount of lead and nine times the safe amount of nickel. None of this is to decry Rishi Sunak’s plan to raise the age for buying cigarettes by one year every year, until the habit is eventually ground out. He has taken commendable political risks in pushing for it against libertarian objections, for this isn’t just about teenagers but about accelerating the process by which smoking starts to feel like a bizarre hangover from the past. Once the legal age for buying fags hits 35, say, will corner shops really be solemnly asking 34-year-olds for their ID? Or will we by then have concluded it’s easier to just ban sales completely, or restrict them to specialist outlets alongside medical advice on giving up? The rarer smoking becomes, the easier it is to restrict with no great outcry – by outlawing it in outdoor public spaces, perhaps, or reducing the nicotine content of tobacco products, as they’re planning in New Zealand (which is also incrementally raising the age limit). Though health charities are delighted by it, this policy is not an answer to the Tories’ current existential problems, so making it the centrepiece of Sunak’s last conference speech before the election suggests that rarest of things: a senior politician doing something because he actually thinks it’s right, backed up by a junior one (in public health minister Neil O’Brien) adept at driving ideas forward. Yet the knottier problem of vaping remains, and that’s where the public health message begins to get unhelpfully complicated. For smokers trying to quit, any risk from vaping is almost certainly smaller than the known deadly risk of still smoking, which is why the NHS advises that switching to vaping is much the healthier option. But if you’ve never smoked, then carrying on avoiding nicotine in all forms would be best. Public health experts worry that vaping is simply leading a generation of kids who wouldn’t otherwise smoke down a different and not risk-free path to nicotine addiction. Were we to find out decades hence that vaping is worse for you than suspected, by then we’d have a population already too hooked to give it up easily. And if that sounds familiar, it’s roughly what happened with cigarettes. In Manchester, Sunak also repeated a promise to crack down on vaping, with a planned consultation on restricting disposable vapes – a market notoriously flooded with cheaply made, counterfeit and black-market versions, prone to contain illegally high levels of nicotine or potentially harmful amounts of heavy metals – and regulating flavours and packaging so they don’t appeal to children. Forcing manufacturers to market vapes as the boring, clinical tool for helping adult smokers that they’re actually supposed to be – no sexier than a blister pack of nicotine gum and definitely not mango ice blast-flavoured – seems thoroughly sensible. Combining that with ramping up enforcement and safety checks to disrupt the black market in illegal e-cigarettes, to protect the health of those already hooked, could well make a difference. But the risk is of this consultation going the same way as Boris Johnson’s obesity strategy – hyped up by its creator, challenged by Liz Truss and finally delayed by Sunak – or the other big public health strategy for protecting children’s lungs: cracking down on air pollution caused by cars. It’s relatively easy to face down big tobacco, an industry that knows it’s dying and has now made its succession plans accordingly. But manufacturers will lobby ferociously to protect the booming market in e-cigarettes into which they’ve diversified. The longer governments drag their feet, the more kids will take up vaping, sucking chemicals into developing lungs with potential longterm consequences we have yet to understand – and one with which we’re already very familiar: that of being suckered into an expensive lifelong nicotine dependency that may keep them hooked long after they want to be. And all the watermelon flavouring in the world can’t sweeten that deal. Gaby Hinsliff is a Guardian columnist