Ed Miliband has accused the Government of taking backward steps on social mobility by allowing inequality to grow and denying bright youngsters from poor backgrounds the chance to succeed.
The Labour leader called for action to open up the "closed circles" in elite professions and make it easier for disadvantaged children to go to university.
But he also attacked the "snobbery" that suggests only an academic education is worthwhile, insisting that the UK must give more respect and value to vocational learning and apprenticeships.
Mr Miliband called for a "new bargain with employers", with Government offering the right support and incentives for them to deliver good training for long-term high-value jobs. And he denounced the Beecroft Report, currently being considered by ministers, which proposes instead reforms of labour laws to make it easier for employers to hire and fire workers.
"The countries that succeed in having a higher-skilled, higher-paid workforce are those where employers and employees show commitment to each other," said Mr Miliband.
"This is the opposite to what this Government wants to do - now considering a proposal from the Beecroft Report to make this short-term culture worse by allowing employees to be fired at will.
"We need an economy based on long-termism, investment, and training. Not the short-term, fast buck, take-what-you-can culture that caused the financial crisis in the first place."
Mr Miliband admitted the previous government should have done more to tackle social mobility but insisted the problem did not get worse under Labour, arguing that the measures it had put in place focused on early intervention so the results would not be seen for many years.
He told the Sutton Trust's conference on social mobility: "The reality is that governments have not got this right for decades. It's not just about qualifications, it's about the culture of the country and what it celebrates and what it doesn't."
Mr Miliband defended the previous government's commitment to 50% enrolment of young people to higher education but admitted Labour had failed to help those who did not continue their studies. He said: "I think the target was right but we didn't do enough to focus on the 50% that didn't go to university." Asked if he would consider means-testing tuition fees, the Labour leader told the London forum all options would be considered when the party drew up its next manifesto.