Rishi Sunak has announced plans to eventually ban smoking by raising the legal age people can buy cigarettes by one year, every year.
It would mean someone who is currently 14 years old will never legally be sold a cigarette.
The prime minister said the change would “save more lives than any other decision we could take” as 64,000 people a year currently die from smoking.
Sunak told the Conservative Party conference in Manchester on Wednesday that his MPs would be given a free vote on the new law.
It means Tory MPs will not be ordered to back his plan if they do not want to.
Sunak said: “We have made great progress in tackling smoking. But if we are to do the right thing for our kids ,we must try and stop teenagers taking up cigarettes in the first place.”
Labour has previously said it would also consider phasing out the sale of tobacco in a similar way.
The proposal mirrors the law in New Zealand, where tobacco cannot ever be sold to anybody born on or after January 1, 2009.
Deborah Arnott, chief executive of health charity ASH, said: “The prime minister has today announced an unprecedented set of measures to protect the next generation and hasten the day when smoking is obsolete.
“Children are four times as likely to start smoking if they grow up with smokers, and once they do it’s highly addictive and difficult to quit.”
In his speech to party members, Sunak said the government would also look at restricting the availability of vapes.
New laws could be brought in that would impact flavours, packaging, point-of-sale displays as well as disposable vapes.