Image caption Would you take a test to buy your cigarettes?

If you're a smoker, could you imagine having to apply and pay for a licence to buy tobacco?

The application process might even include a test to find out if you understood the risks of smoking, and your swipe card licence would limit your tobacco purchases - perhaps to 50 cigarettes per day or less.

It might sound extreme, even social engineering, but this is the proposal of a public health expert in Australia, who suggests that it could provide a practical "disincentive" for smokers.

Prof Simon Chapman from the University of Sydney is interested in the next generation of truly effective anti-smoking measures.

Laying out his case for a smokers licence in the latest issue of the journal Plos Medicine, he said it could be of interest to "high-income nations that are actively pursuing tobacco control goals".

So could a government-issued licence be the best solution to reduce smoking? And how could such a scheme work?

Marketing death

One billion people this century are predicted to die from smoking-related diseases, according to a widely cited paper published in the journal Nature in 2001.

Yet, despite the mortality figures, Prof Chapman says there is still insufficient control of tobacco products, which can be sold by any retailer.

He used the analogy of prescription drugs; prescriptions essentially being "temporary licences" to buy pharmaceuticals.

"In contrast to the highly regulated way we allow access to life-saving and health-enhancing pharmaceuticals, this is how we regulate access to a product that kills half its long-term users," Prof Chapman wrote in the introduction to his paper.

"There would seem to be a case for redressing this bizarre but historically based inconsistency."

The licence that Prof Chapman proposes would be a swipe card; smokers would be required to apply for a card and no retailer would be able to sell tobacco products to anyone without one.

"Penalties for sales to unlicensed persons would be severe," he explained, "with the threat of the loss of a retail licence, as is now the case for pharmacists supplying restricted drugs to anyone without a prescription."

Tied into his scheme would be the requirement for any smoking licence applicant to commit to their own daily limit and of course the periodic inconvenience of renewing their licence. Along with the cost of a licence, Prof Chapman says that all of this could provide some real smoking disincentives.

Questions that could be asked on an application form for a smoking licence If 100 people were diagnosed with lung cancer, how many would we expect to be alive in five years time? What fraction of smokers do you believe will die early because of their smoking? On average, how much longer do non-smokers live than people who have smoked for a long time? A long-term smoker who dies from a disease caused by his or her smoking can expect to lose how many years off normal life expectancy? How many known carcinogens (chemicals which are known to cause cancer) are there in cigarette smoke? Source: Plos Medicine

He also suggests building in a financial reward to entice smokers to quit.

"As a quit incentive, all licence fees paid during a smoker's licensed smoking history would be fully refundable, with compound interest," he explains.

"[And] licence surrender would be permanent and reapplication not permitted."

Prof Chapman is a world-renowned expert in public health issues, but this particular proposal drew criticism even before it was published.

In the same issue of Plos Medicine, Jeff Collin, professor of global health policy at the University of Edinburgh put the case against a smoking licence. One of his main criticisms was that the measure would target consumers rather than the industry.

He went on to say that the licence would be "a gift" for the tobacco industry, which he described as "the world's most powerful disease vector".

While bans on smoking in public places have been broadly accepted as "liberal measures rather than authoritarian intrusions on personal freedom", said Prof Collin, a smoking licence would be vulnerable to attack by the industry, which would deem it "health fascism".

"The proposal plays into the hands of industry attempts to present public health measures as authoritarian, conjuring up a phantom nanny state," he told the BBC.

Extreme measures? Image caption Australian cigarette packets may soon look like this In August 2012, Australia became the first country to uphold a new government law banning brand colours and logos from cigarette packaging. The new rules, scheduled to come into force from December 2012 require cigarettes to be sold in olive green packets, with graphic images warning of the consequences of smoking (pictured)

In a 2010 paper in the journal Tobacco Control, a group of Singapore-based cancer specialists proposed phasing-out tobacco by denying access to tobacco for anyone born from the year 2000 onwards. The researchers said their idea introduced the concept of tobacco-free generations that would "never legally be able to take up the harmful habit of smoking, at any age"

In 2009, the Board of Health of the City of New York adopted a resolution requiring all tobacco retailers to display signs bearing graphic images showing certain adverse health effects of smoking. The rule was overturned by a federal judge in 2010, who ruled that only the federal government had the authority to regulate cigarette warnings and advertisements.

One industry spokesperson made clear the vehement opposition that this proposal would meet. When presented with Prof Chapman's proposal, a spokesperson from British American Tobacco told the BBC: "Asking people to sit a test before they can obtain a licence is an insult, not only to smokers, but to any adult who has the right to make informed choice whether to smoke, and how much to smoke.

"It would be a nightmare to police and hugely expensive to administer, and would criminalise smokers who would be forced to seek out illegal sources of tobacco if they chose to exceed their licensed allowance."

Prof Chapman though, dismissed this argument as "badly flawed".

"The implication here is that many smokers would be similarly willing to transact with criminals," he wrote in his paper.

"[But] while illicit drugs can only be sourced illegally, tobacco would still be readily obtainable legally.

"It is difficult to foresee why significant proportions of smokers would elect to source their tobacco 'underground' dealing with criminals simply because of an easily obtained licensing requirement."

Punishing the poor?

Prof Collin was critical of the scheme's effect on the poorest smokers.

"Core tobacco control measures have long had implications for the poor - most obviously via the use of taxation to reduce consumption," he wrote in the paper.

"A distinguishing feature of this scheme is that, in effect, it would be censuring the poor."

But Prof Chapman suggested that the additional licence fee cost and the fact that it would encourage poorer smokers to quit would be a good thing.

He wrote: "Groups advocating keeping tobacco tax low perversely seek to 'help' poor smokers by keeping tobacco affordable, which encourages use."

Concluding his case for a smoker's licence, Prof Chapman said it would send a powerful, symbolic message to all smokers and potential smokers that tobacco was "no ordinary commodity".

"It would mark tobacco as a product uniquely deserving of such regulation and thereby invite reflection among smokers on why this exceptional policy had been introduced.

"This step may diminish self-exempting views that smoking is just another, unexceptional risk in 'life's jungle'."

And although not supportive of the proposal, Prof Collin agreed that "cigarettes aren't normal consumer goods, and shouldn't be available to purchase any time anywhere".

"From a UK perspective," he added, "the most important next step would be plain packaging, which effectively removes the single most important marketing tool still available to the tobacco industry, the pack itself."

The Department of Health said it had no plans to license the purchase of tobacco products.