Estelle Morris, the Secretary of State for Education, made narrowing social inequality a key priority yesterday and said her job would be pointless unless she succeeded.
She revealed stark figures showing the huge disparity between between middle class children and those from working class backgrounds.
Condemning the "old elitism" in education, Ms Morris said thousands of bright youngsters in inner cities had the potential to go to university but did not.
She told members of the Parliamentary Press Gallery that only four out of seven pupils of manual workers gained expected standards in national tests for 11 year olds, compared with six out of seven for children of the professional classes.
At GCSE level, 68 per cent of children from the social groups A and B gained at least five good grades, compared with 30 per cent from social groups D and E.
The same trend continued at A-level, with 56 per cent of middle class teenagers getting at least one A-level compared with 13 per cent from the working classes, she said.
Only 13 per cent of working class students gained a university place, compared with 73 per cent from the middle classes.
Ms Morris said: "I don't think my job is worth doing unless we can do something to close that gap.
"I think we have stopped focussing on it. I think we have stopped understanding what is going on in those communities where those children are."
She added: "All I aspire for is that if you are poor you are as capable as if you were rich, if you are black you are as capable as if you were white and if you are from the inner city you are as capable as if you were from the suburbs."
The Cabinet Minister said generations of working class people with high aspirations had improved their prospects through education. But she warned: "We have not got over that link between social class and educational attainment."
The Government had laid the groundwork for improvements in secondary school standards but more work had to be done to improve the prospects of working class children, she said.
Her comments echo the debate over elitism, which blew up into a major dispute last year over the Tyneside teenager Laura Spence, who won a scholarship to Harvard after being rejected by Oxford.
Ms Morris said: "The old elitism is still alive you know, among those people who think that expansion to 50 per cent of young people going to university means a lowering of standards."
She added: "We have to start believing in the capacity of our education system to start delivering for poor children, for black kids and in inner cities."
Ms Morris also announced an £11.25 million programme to install computerised registers to cut truancy in 500 schools. Experiments had shown that electronic registration cut truancy by 10 per cent.
"That is another little brick in the wall of trying to get the structure right for our urban schools," she said.
The Department for Education and Skills said the computers would allow teachers to track pupils from class to class, allowing staff to contact parents at once if their children played truant. Schools with truancy problems will be able to choose to join the scheme.Reuse content