Selling tobacco products to anyone born after January 1, 2009 would be illegal if the Tobacco and Vapes Bill were to become law.
It follows that youngsters under the age of fifteen will never be able to lawfully purchase cigarettes.
At the Tory party convention last year, Rishi Sunak unveiled three major proposals, of which the plan was one.
However, the prime minister may now need to rely on support from the opposite side of the Commons to pass the proposal, since a few more pro-business Conservatives have challenged the restriction.
The measures have been characterized as “profoundly unconservative” by Liz Truss, Mr. Sunak’s predecessor, and as “nuts” by Boris Johnson, who is also against the ban.
The proposal is up for free vote among Tory MPs, and many are predicted to vote against it when it comes up for its first full Commons debate on Tuesday.