Modern Britain is still suffering from "deep divides" in society, with a wide gulf between the life chances of the rich and poor, a major report has warned.
There is a growing split by income and by class, with privately educated people still dominating the leading professions and top earners increasing their wealth while more than a million youngsters live in poverty.
While some progress has been made on child poverty, raising employment levels and boosting the academic results of disadvantaged youngsters, this has been limited and remains too slow, according to the Social Mobility and Child Poverty Commission.
In its third annual State of the Nation report, the commission argues that Britain "does not provide a level playing field on which people can aspire to succeed".
While it praises David Cameron and his "One Nation" commitment to cut poverty and improve life chances for all, the hard-hitting report concludes there is a wide gap between this aim and current reality, and that the response is not enough
"The divisions in our nation run deep and, arguably, they are deepening," the commission says.
The Government insisted it is committed to an "all-out assault on poverty".
The report suggests there is no longer just a North/South divide in opportunity and wealth, but that "fissures" have opened up within England, arguing: "It is only 100 miles from Norwich to St Albans, but they are like two different countries."
On average, men live three years longer and women nearly two years longer in St Albans than in Norwich. The average salary is around £13,000 higher in the former and there are nearly twice as many professional jobs.
Unemployment in Norwich is almost double that of St Albans, children are over three times as likely to be in low-income families and much less likely to gain five good GCSEs.
The report warns there is a "growing social divide by income and by class" across Britain.
While the income share of the top 10% has increased from 28% to 39% since 1979, and the income share of the top 1% has gone from 6% to 13%, at the other end of society, there are more than a million children living in persistent poverty, who do not have access to many of the opportunities available in modern society, it says.
The commission, led by former Labour minister Alan Milburn, also takes aim at the exclusivity of many top professions, saying "those who rise to the top in Britain today look remarkably similar to those who rose to the top half a century ago".
Around 71% of senior judges, 62% of senior armed forces officers and 55% of civil service department heads attended private schools, which collectively educate around 7% of the population.
"Of course, the best people need to be in the top jobs - and there are many good people that come from private schools and go to top universities. But there can be few people who believe that the sum total of talent resides in just 7% of pupils in the country's schools."
The report sets out a series of recommendations to boost social mobility, covering areas from early years and schools to apprenticeships, universities and employment.
Mr Milburn said: "At current rates of progress it would take at least 30 years for the educational attainment gap in schools between poorer children and their better-off classmates to even halve. It would take over 50 years before the gap in access to university is closed between the areas with the lowest and highest participation rates.
"There are many reasons to be optimistic about the future but progress towards a One Nation Britain is too limited and too slow. In our report we call on governments across the UK and educators and employers to move up a gear."
A Government spokesperson said: "This Government is committed to an all-out assault on poverty.
"Our investment in childcare is helping parents get into work and give their children the best start in life, while the pupil premium and school reforms are ensuring every child gets a good education.
"Work is the best way out of poverty and with a stronger economy we now have record numbers in work and the number of workless households is at a record low.
"We are introducing the national living wage, we are committed to three million more apprenticeships by 2020, we are funding 30 hours of free childcare for working parents, and the pupil premium and schools reforms are ensuring every child gets a good education."