More must be done to help children from poor backgrounds convert early promise into continued academic success, according to a new report.
Disadvantaged children who start out as high attainers are overtaken by better off children who were initially only average attainers, the study found.
The Social Mobility and Child Poverty Commission has published new research by the Institute for Fiscal Studies looking at the educational performance of disadvantaged children.
It discovered that nearly 2,200 fewer poor children are attending elite universities than would be expected if they followed the same educational trajectory throughout secondary school as their better off peers with similar levels of attainment at age 11.
Only 9% of children from the most deprived families reach level 3 in reading and maths at age seven (a measure of high achievement), compared to 27% of the least deprived children.
By age 11, only 7% of pupils who claim free school meals throughout secondary school achieve level 5 in English and maths, compared to 19% of those not in this group.
The study suggests that the early promise shown by the brightest poor students can be lost as they progress through school, particularly between ages 11 and 16.
Action is needed to ensure that secondary schools provide pupils with the support and guidance they need to convert early attainment into continued academic success.
Commission chairman Alan Milburn said: "This research shows that Britain is wasting young talent on an industrial scale.
"Each year, 2,000 of the brightest poorest children who have done well at primary school seem to lose direction in a secondary school maze and so miss out on a top university place.
"The early promise of top-performing poorer children is being squandered. No doubt there are many reasons why that might be the case. But for secondary schools the research is a wake-up call for them to do more to realise the potential of each of these students.
"It is vital that secondary schools focus harder on helping disadvantaged children convert high results at age 11 to excellent GCSE and A-level results in academic subjects and that all high attainers are given appropriate advice, access to opportunities and support to progress to elite universities.
"If Britain's sluggish rates of social mobility are to improve the poorest brightest children must be helped to navigate the secondary school maze."