Children from poor backgrounds are less likely to go to university than equally bright counterparts from wealthier families, even if they live in the same area and have similar GCSE results, research has found.
The Social Mobility Commission (SMC) findings reveal a progression gap between choices made by children on free school meals and their more affluent peers which cannot be explained by exam results or where they live.
Commission chairman Alan Milburn said the report indicated "something is going badly wrong" and suggested the lack of proper careers advice and the complexity of the post-16 education system made it harder for poorer children to fulfil their potential.
Analysis by Education Datalab for the SMC found that just 24% children eligible for free school meals go on to higher education compared with 42% from more privileged backgrounds.
Poorer children are also twice as likely to drop out of education at 16.
The researchers found 20 areas of England with little or no school sixth form provision within a commutable distance.
In these areas, there are significantly lower percentages of pupils studying for academic qualifications at 16, attending a top university or studying for a science or maths degree compared with similar areas.
Young people growing up on London have, on average, 12 post-16 institutions to choose from, while those in the North East and the South West have an average of seven colleges or sixth forms to which they can commute.
Just 36% of white British students go to university, but children from ethnic minorities were more likely to, including up to 72% from Indian backgrounds.
Former Labour minister Mr Milburn said: "When low-income youngsters from the same area with the same school results are progressing less than their better-off classmates, that is not about lack of ability. It is about lack of opportunity. The progression gap has many causes but it suggests something is going badly wrong in our education system.
"The lack of proper careers advice in schools and the sheer complexity of the post-16 education and training system make it particularly difficult for lower income youngsters to translate their attainment at school into qualifications that are well rewarded in the labour market.
"That has significant consequences for social mobility and leads to many young people becoming trapped in low-skilled, low-paid jobs.
"Government and schools should be working to create more of a level playing field of opportunity for youngsters to progress."