Rishi Sunak says he is “disappointed” his bill banning young people from ever being able to smoke legally will not pass before the general election.
The Tobacco and Vapes Bill, external is not included in the legislation being rushed through by MPs ahead of Parliament shutting down on Friday.
Selling tobacco to anyone born after 1 January 2009 would have become illegal.
But Mr Sunak said the bill was “evidence of the bold action that I’m prepared to take”.
“That’s the type of prime minister I am. That’s the type of leadership that I bring.
“I stepped up to do something that is bold, that will make an enormous difference in the future of our country.”
Labour’s shadow health secretary Wes Streeting said: “If Rishi Sunak’s idea of bold leadership is to crumble before his party and surrender his landmark smoking bill, it’s no wonder the country is in such a mess.”
Labour remained committed to the policy and would “make sure that young people today are even less likely to smoke than they are to vote Tory”, he added.
Speaking to reporters on a flight from Belfast. the prime minister did not promise a ban would feature in the Conservative manifesto, but he said he remained “very committed” to it.