School admissions and parental choice are fuelling segregation, says the man in charge of England's admissions.
Poorer children tend not to have good schools close by
Instead they should be used to limit social and racial division, says chief schools adjudicator Philip Hunter.
Schools with a high number of difficult-to-teach pupils were not being given a chance and needed help.
Admissions lotteries could be brought in or schools could be closed, with their pupils dispersed, or they could be reopened as academies, he said.
Dr Hunter's warning comes as more than half a million children are about to find out whether they have got their first choice of secondary school.
He said: "It's a myth to say there's a system where everybody is achieving their first choice school."
But he added that the current system was letting too many disadvantaged pupils down.
"It leads to a position where some schools have got such a high proportion of children from difficult backgrounds that there's no chance at all."
This was because schools that lacked enough pupils from backgrounds with high expectations for them found it very hard to succeed.
The issue was a "hugely politically explosive one", but it had to be addressed in the interests of social cohesion, he said.
There needed to be more regulation of school choice and this would mean bad news for families who had bought their way into a good school's catchment area.
"What we are doing is saying to one group of parents, I know you paid £20,000 more for this house than you wanted to in order that your children can go to the local school, but we are saying that some of you can't get in - in order to make room for some child from that difficult estate."
Various solutions were possible, said the chief school adjudicator. These included:
- Closing down schools and re-opening them as academies
- Dispersing pupils on free school meals to a wider number of schools
- Altering admissions arrangements and introducing systems such as lotteries
Dr Hunter said it would never be possible to ensure every school has the same number of pupils on free school meals.
But that current admissions code gives clear instructions that local authorities and local schools should monitor what is going on.
They should be intervening when some schools are put at a disadvantage because they have too many pupils from difficult backgrounds.
However, he added: "We are not going to see kids bussed from Harpenden to Hackney and back again.
"But there are going to be some areas where they move away from the distance criteria for deciding who gets priority and moving more to ensuring that very high achieving schools do get their share of children from disadvantaged backgrounds."
Schools Secretary Ed Balls said it was his government's policy to make all schools good schools.
"Those who use poverty and deprivation as an excuse for poor performance are letting children down," he added
Academies - independently run but publicly funded state schools - were improving results in disadvantaged areas faster than those with a comparable intake, he said.
This was why the government was announcing an acceleration of the scheme by five a year. This means some 243 academies would be built by 2010 instead of the planned 233.
Mr Balls made the announcement at Labour's spring conference, adding that £500,000 would be cut from the set-up costs.