New research today lays out just how much of an advantage a private education still buys you in modern Britain.

The Institute for Fiscal Studies (IFS) has found that the average privately-educated person earns 6 per cent or £1,500 a year more than a state-educated colleague who has the same qualifications and is doing the same job.

The study provides more evidence of a lack of social mobility and the continuing dominance of fee-paying schools in the UK. How bad is it?

Private – Keep Out

The Independent Schools Council estimates that only about 6.5 per cent of school children in the UK are educated in the independent sector.

Pupils who go to fee-paying schools are disproportionately more likely to go on to higher education and to attend top universities like Oxford and Cambridge, according to the Higher Education Statistics Agency (HESA).

The latest HESA figures from 2012/13 show that only 57.4 per cent of young undergraduate entrants to Oxford University were state educated compared to the UK average of 89.3 per cent, and the state-school proportion was down on the year before.

A study published last year by the University of London’s Institute of Education found that 16.9 per cent of people working in Britain’s top jobs (“higher managerial, administrative and professional occupations”) are privately educated.

And the government’s Social Mobility and Child Poverty Commission has published figures showing how some important professions are dominated by people who went to fee-paying schools. What do we learn today?

We already knew there was a “private school premium” in the sense that the privately educated earn more on average.

That’s not really surprising, because they tend to have more money in the family, go to better universities, choose different courses and enter more prestigious professions.

The really interesting thing about the new IFS paper is that it controls for all these factors and there is still a difference in income.

The researchers tracks individuals who graduated from UK universities in 2006-07 and track their earnings three-and-a-half years after graduation.

By that time, someone who went to private school can expect to be earning 6 per cent or £1,500 a year extra, compared to a state-school pupil with the same background, education and occupation.

The authors say: “There is a pressing need to understand why private schooling confers such an advantage in the labour market, even amongst similarly achieving graduates, and why higher education does not appear to be the leveller it was hoped to be.”

Is this study unusual?

No, plenty of other research confirms the existence of a private school premium.

A 2002 study found that the independently educated could expect to get paid about 3 per cent more in their first job, controlling for family background and educational achievement.

It also found that the wage premium went up with the level of fees charged by the school – but not with the average academic performance of the school.

The Traditional Wall Game At Eton

Eton schoolboys take part in the Wall Game (Getty)

Academics are still at a loss to explain why this happens.

The Institute of Education paper discounted the theory that social networks give the richest students a big advantage when it comes to getting top jobs.

The authors suggest other explanations for the private school advantage: more confidence and self-esteem; the ability to “exhibit desirable behaviours and conversations in the interview setting”; the resources to spend more time looking for work or doing unpaid internships.

Is social mobility getting worse?

This is a complicated question. There are different definitions of social mobility and a number of ways of measuring it.

As we found in an earlier FactCheck, people often believe that things are worse now than in the supposed golden age of the 1950s and 1960s, with many blaming the demise of the grammar school.

The leading sociologist Dr John Goldthorpe has tried to shoot down that theory, saying: “No decline in mobility, absolute or relative, occurred in the late twentieth century.”

That doesn’t mean things are great now, it just means that British society did not really become more open after the Second World War, as many people assume.

And this paper suggests the grammar school system did not improve social mobility for society as a whole.

Some individuals may have benefited from going to grammar school, but others were disadvantaged by going to a secondary modern, and the two cancel each other out.

One really pessimistic view is set out by US academic Gregory Clark, who tracked unusual surnames over hundreds of years to trace the rise and fall of rich families.

He found that privilege and advantage can endure for many centuries: “If your surname is rare, and someone with that surname attended Oxford or Cambridge around 1800, your odds of being enrolled at those universities are nearly four times greater than the average person.”

In fact, his depressing conclusion was that social mobility in Britain is no better now than it was in the late middle ages.