Social mobility in the UK has not improved since the 1970s, despite ten years of a Labour government, a report by the Sutton Trust finds today.
Based on research by the London School of Economics and University of Surrey, the report concludes educational success is still "overwhelmingly tied" to parental income.
The researchers found the brightest but poorest children were likely to drop from the 88th percentile to the 65th when tested at three and five years old.
In contrast, the least able children from better-off families rose from the 15th to 45th percentile throughout the same period.
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This trend continued and deepened throughout children's school careers, with just ten per cent of the poorest fifth of children earning a degree in 2002, compared to 44 per cent of children from the most affluent backgrounds.
A comparison with other countries shows UK children are among the least likely internationally to rise above their parents' background.
Sir Peter Lampl, chairman of the Sutton Trust, said: "Shamefully, Britain remains stuck at the bottom of the international league tables when it comes to social mobility.
"It is appalling that young people's life chances are still so tied to the fortunes of their parents, and that this situation has not improved over the last three decades."
The findings are based on looking at children born between 1970 and 2000. The report does note that life chances were worse for children born in the late 1950s, while ministers are keen to point out that it remains to be seen how the post-2000 cohort of children will perform.
Sir Peter called for a radical review of the government's approach to social mobility, arguing an independent commission should be tasked to look at the underlying causes of low mobility.
The government insists the previous decline in social mobility has now been stabilised, while a raft of initiatives have been introduced to improve educational attainment.
Children's minister Beverley Hughes said the government's reforms will show progress soon.
Ms Hughes said: "This new research is based on the Millennium Cohort born in 2000-01. It's far too early to say what will happen to those young people over their lifetime.
"Those children have yet to enter key stages two, three and four, where overall standards are continuing to rise and poverty gaps have narrowed since 2003."
She insisted the government has already made "encouraging progress" towards improving social mobility but has "always said" it needs to do more to narrow the attainment gap.
Ms Hughes continued: "We can only tackle deprivation and poverty by changing the aspirations of young people, their parents and the education system. We have always known that parents are the most important factor in a child's educational achievement."
She touted this week's Children's Plan as proof of the government's commitment, predicting it would ferment a "revolution" in the way parents engage with their children's education.
The Liberal Democrats, however, argued the government needs to move away from "gimmicks and reviews" and instead tackle the inequality at the heart of the education system.
Lib Dem schools spokesman David Laws said parental background continues to have a massive impact on attainment and as such the government must increase the take-up of early years education among children from the poorest backgrounds.
Mr Laws said: "Unless we intervene in the early years, educational success will remain the domain of the better off and poorer children will continue to be left behind."