Michael Gove warns that schools are failing on social mobility
The schools system in England is failing poorer children "at every turn", says the Shadow Schools Secretary, Michael Gove.
He says initiatives to close social inequalities in exam results and staying on rates are not succeeding.
But the Conservatives say they have no plans to scrap the maintenance allowance to keep youngsters in school.
Schools Minister Jim Knight says that "Tory policies would simply preserve excellence for the few".
Mr Gove's speech asserted his party's commitment to strengthening family life, promoting responsible fatherhood and supporting children from the most deprived backgrounds.
"Schools should be engines of social mobility, the places where inherited disadvantages are overcome and individual talents can be nurtured to make opportunity more equal," Mr Gove told the IPPR think tank.
"But the record of this government has been of inequality growing, and the opportunity gap widening, between the fortunate and the forgotten.
"In the last year for which we have figures the gap at GCSE between the performance of students in the 10% of wealthiest areas and the 10% of poorest areas doubled."
Mr Gove's speech highlighted the lack of success for pupils on free school meals at the basic level and among the high-flyers.
He warned that 47% of such poorer pupils did not achieve a single GCSE at grade C - and that only 176 pupils eligible for free school meals had achieved three A grades at A-level - less than 1% of the total.
The Conservatives have also argued that there has been too little progress in poorer pupils staying on at school beyond the age of 16, despite the introduction of the education maintenance allowance (EMA).
But a party spokesman said that there were no plans to stop the EMA, which gives financial support to keep youngsters in education.
Mr Gove also spoke of his support for the Sure Start scheme to help families with young children.
Schools Minister Jim Knight rejected the claims that the government is failing to tackle the achievement gap between rich and poor pupils.
He pointed to the current "National Challenge" which has set a deadline to ensure that all secondary schools in England, including those serving the most deprived areas, achieve at least 30% of pupils getting five good CGSEs.
Individual catch-up lessons in reading, writing and maths, the forthcoming Diplomas and raising the leaving age to 18 would all be steps to supporting children from poorer backgrounds, he said.
"If the Tories were serious about improving outcomes for the poorest children, they would support our plans to strengthen local children's trusts, drop their pledge to cut funding to Sure Start and finally commit themselves to our ambitious targets on child poverty."