Plans to phase out the sale of cigarettes in England will be the “biggest public health intervention in a generation”, Rishi Sunak has said.
The PM told the BBC there was “no safe level of smoking” when asked about restricting people’s right to choose.
His plan seeks to raise the legal age of smoking every year by a year so that eventually no-one can buy tobacco.
Tory MPs will be allowed a free vote while Labour indicated it would back the policy.
But some critics of the policy say it could lead to the creation of a “black market”.
Last year, the tobacco industry raised more than £10bn in taxes, a 3% drop from 2021-22.
Making the announcement in his keynote speech at the Conservative Party Conference, Mr Sunak said he believed it was the right step to tackle the leading cause of preventable ill-health.
Originally scheduled for this month, plans to ban two-for-one junk food deals have been delayed by the government for another two years.
But Mr Sunak told the BBC smoking cigarettes was not the same as eating crisps or a piece of cake because it could not be part of a balanced diet and there was no safe level of smoking.
“Smoking is unequivocally the single biggest preventable cause of death, disability and illness in our society,” he said.
“Everyone recognises this measure will be the single biggest intervention in public health in a generation.”
He said measures to restrict choice were “never easy” but nobody would want their children or grandchildren to grow up to smoke.
Smoking increases the risk of strokes, heart disease, dementia and stillbirth as well as causing one in four deaths from cancer.
Smoking rates have been falling since the 1970s. But there are still more than five million smokers in England and six million across the UK.
Currently, one in nine 18 to 24-year-olds smokes, according to the Office for National Statistics.
The idea of gradually increasing the smoking age was put forward last year by Javed Khan, the former Barnardo’s chief executive, who was asked by ministers to consider new approaches to tackling smoking.
At the time, the government, which was led by Boris Johnson, said such a move was unlikely.
But Mr Sunak has decided to throw his backing behind it as a way of meeting the government’s ambition for England to be smokefree by 2030 – defined as less than 5% of the population smoking.
The proposal to raise the age of sale of cigarettes is similar to laws being introduced in New Zealand, where buying tobacco products will remain banned for anyone born after 2008.
Setting a legal smoking age is devolved in Scotland, Wales and Northern Ireland. The Welsh government has said it plans to copy the ban, while the Scottish government has its own plan to make Scotland tobacco-free by 2034.
Sir Chris Whitty, the Chief Medical Officer for England, has said “the overwhelming majority of the medical profession, the nursing profession and all the health charities support this”.
He described claims from the tobacco industry that the ban would not work as “bogus”.
Speaking to the BBC, Sir Chris said: “As a doctor I’ve seen many people in hospital desperate to stop smoking because it’s killing them and yet they can not – their choice has been removed.”
Labour said it would “not play politics with public health” and would lend the prime minister the votes to get the law passed – but the plan is likely to meet opposition from the libertarian wing of the Conservative Party.
Earlier this week, former prime minister Liz Truss said the party needed to “stop banning things”. It is understood she will not vote in favour of the policy.
Christopher Snowdon, head of Lifestyle Economics at the Institute of Economic Affairs think tank, told the BBC the policy if implemented would lead to “massive black markets”.
“You’re going to have, almost certainly, a fairly large, informal market of smokers who are old enough to buy cigarettes selling cigarettes to people who are not old enough.
“The problem with prohibition isn’t that it doesn’t have any effect whatsoever on consumption, the problem with prohibition is it leads to massive black markets and a lot of tax revenues gone.”
Simon Clark, director of the smokers’ rights group Forest, accused the prime minister of “dumbing down” by treating future generations of adults like children.
He added that Mr Sunak had taken a “wrecking ball to the principles of choice and personal responsibility”.
But Cancer Research UK’s Michelle Mitchell said the announcement on the smoking age was a “critical step”.
“If implemented, the prime minister will deserve great credit for putting the health of UK citizens ahead of the interests of the tobacco lobby.”
Deborah Arnott, from campaign group Action on Smoking and Health (ASH), said what had been announced was an “unprecedented” set of measures which would hasten the day smoking is obsolete.
Also in his interview with the Today programme, Mr Sunak:
While Mr Sunak undoubtedly hopes his plans to phase out smoking will be a legacy of his time in office, his first conference as PM was overshadowed by his decision, and the speculation in the days leading up to it, to axe the northern leg of the HS2 rail project.
While critics reacted with anger to the decision, the PM insisted investments would instead be made in transport projects across the country.
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