LONDON — Britain is poised to launch a world-leading project to create a “smoke-free generation” by raising the age to legally buy cigarettes each year.

The legislation would ban the sale of cigarettes to anyone born after 2009 – and then every year, the legal age would rise so that the prohibition would follow the generation indefinitely. Vaping, however, would not be affected and instead would be subject to other restrictions.

Parliament was expected to debate the law and then vote on it Tuesday evening, and Prime Minister Rishi Sunak has given his party a “free vote” on the bill, meaning members do not have to follow his lead in voting. The ban has deeply split his Conservative Party, and many of its lawmakers decry it as a measure of the “nanny state.”

The opposition Labour Party, however, supports the measure, so it will probably pass.

Smoking itself would not be subject to fines. Older smokers would be allowed to continue to buy tobacco until they quit – or die.

The legislation does seek to make vaping less attractive, by changing the packaging – from today’s candy-colored pastels – and by outlawing the popular disposable inhalers that can be found littering city sidewalks.

Sunak is spearheading the campaign, arguing that smoking kills tens of thousands of people each year, with most smokers starting in their teens.

As in much of the world, smoking rates have declined in Britain (as vaping has increased). About 1 out of every 8 people in Britain smoked last year – some 6.4 million people. Smoking rates among teens remain high, with more than 12% of 16- and 17-year-olds smoking in England.

Sunak, who does not drink alcohol or smoke, and who is reported to fast one day a week, argues that saving lives is the conservative thing to do.

Leading figures in his party have expressed their opposition, arguing that if people want to smoke, it’s not the government’s job to stop them.

Sunak’s predecessor, Liz Truss, the shortest-serving prime minister in British history, has dubbed the bill the ill-considered work of a “nanny state.”

Truss told the BBC, “We’re a free country. We shouldn’t be telling people not to smoke, and I worry about where it will lead.”

Boris Johnson, another former prime minister from the Conservative Party, told a gathering in Canada last week that the proposed ban was “absolutely nuts.”

Lamenting the state of his party, Johnson observed, “When I look at some of the things we are doing now, or that are being done in the name of conservatism, I think they’re absolutely nuts.”

“We’re banning cigars. What is the point of banning – the party of Winston Churchill wants to ban cigars! Donnez-moi un break, as they say in Quebec. It’s just mad,” he said, using one of his trademark quasi-French phrases.

Johnson resigned as prime minister under pressure from his own lawmakers for repeatedly misleading them over parties held at 10 Downing Street during the covid pandemic. Later he abandoned his seat in Parliament and is now making a living writing columns for the Daily Mail and appearing on panels on the international lecture circuit.

Chris Whitty, chief medical officer for England, who served under Johnson during the pandemic, says his old boss has got it wrong.

“Those people who say it’s all about choice completely misunderstand smoking,” he told ITV on Tuesday, stressing that nicotine is highly addictive and that smokers find it extremely difficult to quit.

“Calling things names isn’t really a serious argument,” Whitty said, asking who would want to return to the “very, very much worse” health of British citizens in the 1940s, when smoking was rife.

In an opinion piece in the Guardian, Whitty charged that lawmakers were being aggressively lobbied by tobacco and vape companies to frame the issue as one of “choice” vs. “ban.”

Whitty said the tobacco industry was the only one to gain from cancers and heart disease. “They try to link their products to ‘choice’ despite the fact their sales are based on addiction.”

Other Conservative Party figures, including Kenneth Clarke, a former health minister who now serves in the House of Lords, worried the measure might be hard to enforce.

He imagined a time – decades to come – when “you will get to a stage where if you are 42 years of age, you will be able to buy them but someone aged 41 will not be allowed to.”

Clarke told the Telegraph newspaper, “Does that mean you will have to produce your birth certificate? It may prove very difficult to enforce. Future generations will have to see whether it works or not.”

Sunak’s legislation was inspired by New Zealand, which last year passed the toughest anti-tobacco laws in the world, intended to ban sales to those born after Jan. 1, 2009, as well as cut nicotine content and slash the number of tobacco retailers.

Instead, the country’s new government in February announced that it will scrap the rules to help pay for tax cuts – and because, in its estimation, the ban could create an illegal black market that would be hard to control.