Who will benefit from the new school admissions code?
With its proposed changes to the school admissions code published on Friday, the government wants to allow academies and free schools to give priority to the poorest pupils when allocating places.
So is the school admissions system in England being turned on its head - and if so, which way?
Are we looking ahead to a new era of equality of opportunity? Or are the hard-working middle classes being squeezed out in favour of the poorest?
Or are ministers trying covertly to bolster the elite?
The changes are likely to raise some middle-class hackles, especially among those who take on big mortgages to buy homes in catchment areas in the hope of getting their children into popular schools.
Indeed, journalist Toby Young, who is setting up one of the first free schools, said the admissions changes would "enable successful free schools and academies to ensure children from low income families aren't crowded out by sharp-elbowed, middle class parents".
But the proposed rules have not gone down well among some advocates for comprehensive education, like campaigner Fiona Millar, who demand to know why the proposal should not be extended to all state schools.
After all, times are lean and there is money at stake - £430 a year goes to the school for every student on free school meals that it takes under the newly introduced "pupil premium".
But even so, the Association for School and College Leaders said this wasn't much, given the cost of supporting some pupils from the most deprived backgrounds.
However, there are already school and local authority mechanisms which keep the doors open to the disenfranchised (or undermine aspirational home buyers) like academic banding systems.
Currently state schools - apart from grammar schools - are not allowed to select on the basis of academic ability.
But they can, and some do, use "ability bands" to ensure a balanced intake - by testing pupils' ability, and then admitting a proportion from every level or band.
But banding can, in theory, work both ways - ensuring a high proportion of high, or low, performing children. This is because schools are allowed to band to represent the national picture, the local picture, or the range of applicants.
Thus if a school in a locality full of high-performing children bands in line with the national average, it could end up turning away bright pupils who live nearby in favour of less well performing ones from further away.
But if the same school banded on the basis of its locality, it would take a larger proportion of high performing children, perhaps at the expense of children likely to achieve lower grades.
This system remains largely unchanged in the new code.
Another issue has been lotteries, where random selection is used, either by individual schools or local authorities, to allocate places.
Drawing lots gives everyone a chance, but it also undermines middle-class parents' chances of securing a place in a popular school by buying a home nearby.
In the new code, the government is to ban lotteries across whole local authority areas - although they were not widely used anyway - saying these can leave pupils having to travel large distances if chance allocates them a school far from home.
However, individual schools will still be allowed to hold lotteries.
Education Secretary Michael Gove argues that allowing good schools to expand will create more good school places, and so increase choice.
However, there are also concerns that the admissions code changes will work the other way, hitting struggling schools and therefore the children who attend them, who are often those in deprived areas.
Some teaching unions fear that by removing the requirement for schools to consult with the local authority, which manages school places across an area, expansion in one school might hit others as pupils move elsewhere with little warning, taking "per pupil" funding with them.
Russell Hobby, of the National Association of Head Teachers, said he was "not unhappy" with allowing schools to expand.
"I just want to make sure its coordinated so you're not kicking other schools in the teeth as you do it".
He is also concerned about the removal of the stipulation that, when drawing school catchment areas, schools "must not exclude particular housing estates or addresses in a way that might disadvantage particular social groups" - and that choices of feeder school should not "unfairly disadvantage children from more deprived areas".
The new code says only that catchment areas should be "reasonable" and "clearly defined".
Academy trusts, and the governing bodies of some faith schools, act as the school's own admissions authority, so can set their own catchment areas and feeder schools.
Mr Hobby said the new wording created the opportunity for schools to "manipulate" catchment areas, "drawing the lines on the right side of the tracks, not the wrong side".
Shifting the balance?
The government, however, points out that parents have redress through the schools adjudicator, if policies or decisions are considered unfair.
The move to prioritise pupils on free school meals is still only a proposal - actually just a footnote in the code which will now be put out for consultation.
If implemented, it is another tool for some schools, if they choose to, to shift the balance in favour of poorer pupils - but it does not apply to all schools.
And while there are already other methods which can be used for similar purposes, there is clearly concern that other changes to the code will leave open ways for schools to tilt their admissions towards high achievers.
There's little disagreement that the fairest thing is a school system where every child, regardless of background, has access to a good school.
But how this should be brought about - and how to make things as fair as possible in the meantime - remains hotly debated.