Private schools have become "divorced from normal life" and will face "tougher" tests to justify their charity status, Theresa May announced on Friday (9 September).
"Most of the major public schools started out as a route by which poor boys could reach the professions, the nature of their intake may have changed today, indeed these schools have become more and more divorced from normal life," the Conservative premier said.
"Between 2010 and 2015, their fees rose four times faster than average earnings growth, while the percentage of their pupils who come from overseas has gone up by 33% since 2008. But I know that their commitment to giving something back to the wider community remains."
She added: "Through their charitable status, private schools collectively reduce their tax bills by millions every year.
"I want to consult on how we can amend Charity Commission guidance for public schools to enact a tougher test on the amount of public benefit required to maintain charitable status."
The plan is part of a major shake-up of the education system by May. The proposals include a lift on the ban on new grammar schools, which were phased out over the 1960s and 70s and were later outlawed under New Labour in 1998.
May's move has proved controversial since the schools typically select pupils based on a general attainment test at the age of 11.
Sir Michael Wilshaw, the chief of schools watchdog Ofsted, has criticised the policy as "nonsense", while Labour accused May of "harking back to a golden-age that never existed. We are supporting the most diverse schools system that we have ever had in our country," the prime minister said on Friday.
May also wants to relax admission rules for faith schools, which will allow new Catholic schools to open in England. Current regulations mean there is a 50% cap on faith-based admissions to faith schools.
Liberal Democrat leader Tim Farron, speaking ahead of May's speech, said: "If the Conservatives are serious about improving our schools, they should reverse the cuts they have made to schools' budgets."