Parents are prepared to move house or lie to win a place for their child at a good school, a study has suggested.
Poorer children tend not to have good schools close by
Half of the 1,255 adults polled for the Children's Society said they would move home to get into a good state school's catchment area.
And one in seven said they would give a false address or fib about their faith to escape the "schools lottery".
Ministers said the schools admissions code was designed to outlaw unfair and covert admission practices.
Chief executive of the Children's Society Bob Reitemeier said the lengths parents were prepared to go to clearly indicated there were huge variations in school standards.
"But for many parents, the costly exercise of moving house to get their child into a good school is simply not an option.
"The current system is in danger of embedding inequality by making a child's social class and economic circumstances the key influencer in their educational success."
Poorer children tend to not have good schools close to their homes, research has suggested.
Some 44% of children eligible for free school meals have a good school nearby compared to 61% of their peers, according to government research.
A Department for Children, Schools and Families spokesman said it was already giving parents more choice by increasing the number of good schools.
"More maintained schools than ever before have more than 70% of pupils getting five A*-C passes or more, trebling from 248 in 1997 to 768 this year."
Parents were also being given more power to help make every school a good one, while local authorities now had clear new duties to increase opportunities for parental choice, he added.
Shadow schools minister Nick Gibb said the results underlined the need for more good schools.
"Too many children do not have access to schools with the proven successful characteristics such as setting by ability and a strong approach to discipline.
"There is no reason why schools in disadvantaged areas shouldn't perform well - we need to start by spreading best practice from the most successful schools across the board."
Official statistics show 14,930 appeals against allocation of school places were heard by an independent panel last year - up slightly on the previous year.
Ministers say the figures show the vast majority of parents are happy with the place allocated to their child.