Poor pupils could be given priority over their wealthier peers under changes to the admissions code being considered by Michael Gove.
The Education Secretary "floated an idea" this week to rip up the admissions code enabling free schools and academies to give preference to pupils from disadvantaged backgrounds.
It is understood that these schools would be allowed to select poorer pupils allowing them to capitalise on the proposed pupil premium, which will give additional cash to schools which admit pupils on free school meals.
A source close to Mr Gove said: "At the moment it is just an idea, and we will set out what we plan to do in the white paper. The proposals emulate the charter schools in the US, which look after the poorest kids."
But the move has attracted criticism from teachers' leaders, who have described the idea as "nothing more than window dressing" and the possible end to the admissions code.
Mary Bousted, general secretary of the Association of Teachers and Lecturers, said: "Most schools will not take up the offer because often these children are much harder to educate. They will be too worried about their position in league tables, getting the requisite GCSEs and being successful than to have their heads turned by this."