Theresa May has laid out her plans for a new generation of grammar schools to Conservative MPs, saying she wants an "element of selection" for a "21st century education system".
The prime minister told the 1922 Committee of backbench Tories the education system already has "selection by house price", according to sources who were at the meeting.
On Tuesday it emerged the government was plotting to back new grammar schools when secret Cabinet papers signed by the Department for Education's most senior civil servant were accidentally exposed to photographers in Downing Street.
It followed reports last month in the Sunday Telegraph that Mrs May was planning to lift a nearly two-decade ban on the establishment of new grammar schools, allowing for a wave of new selective schools.
The papers photographed in Downing Street this week revealed that Education Secretary Justine Greening's "clear position" is that they should only be approved once ministers have worked with existing selective schools to show that pupils who do not make the grade are not disadvantaged.
In an effort to pacify concerns that new selective schools may damage social mobility, Mrs May told the 1922 Committee she wanted new grammars to be "inclusive and not exclusive".
The plans have been backed by several Conservative-linked pressure groups and think-tanks but have drawn criticism from opposition parties, unions and other independent organisations.
Earlier this week, Sir Michael Wilshaw, the Government's outgoing chief inspector of schools, dismissed the selective model and said it would fail the poorest children.
Labour has accused Mrs May of favouring an education system that will only cater for the "select few" while unions have suggested her plans are elitist.