Children who attend private school will earn £193,700 more on average between the ages of 26 and 42 than those who go to state schools, a new analysis suggests.

The report from think tank the Social Market Foundation also found that privately educated people earn 43 per cent more per hour by the age of 34, although this drops to 34 per cent more at the age of 42.

The researchers conclude that a wide range of factors may have an impact on earnings, but that better educational achievement plays a major role.

It finds that on the best available evidence - value-added scores - independent schools, on average, help their children progress more during their school years than state schools.

The figures came out as part of the think-tank’s analysis of the Sutton Trust’s proposed Open Access programme, designed to increase the numbers of children from poor backgrounds able to attend private schools.

Under the scheme, participating schools would receive the same funding per pupil as local state-funded schools, but also charge fees on a means-tested basis, with the poorest families paying no fees.

Using the latest data on independent school fees, the researchers estimate that applying the scheme across 100 leading independent schools, covering 62,000 pupils, would cost the government around £215 million per year.

A wide number of leading independent schools have signed up to take part in the scheme, but the government is has not given it the go-ahead.

Emran Mian, director of the Social Market Foundation said: “Our research shows that pupils from independent schools do dramatically better than those who go to state school … these huge differences arise in part because these children come from privileged backgrounds anyway.

“But that’s not the whole story. Take two people of the same ability at age 11 and with the same parental background, track them forward, and the pupil who attends independent school is likely to earn substantially more.

“A significant driver appears to be simply that independent schools typically progress the education of pupils more during their school years than state schools. On this basis, limiting the opportunity to attend independent schools to those who are able to afford the high fees seems inequitable.”

Sir Peter Lampl, chair of The Sutton Trust added: “This report clearly sets out the advantages that can be gained from a good private education. We need to open those opportunities to more young people, transforming the independent sector to ensure that successful day schools recruit once again on merit rather than money.”

The report comes less than a week after a study by the Social Mobility and Child Poverty Commission found that more than 2,000 of the “brightest and poorest” pupils were missing out on places at  top univeristies to pupils from independent schools.

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Subjects have a greater impact on social mobility than school type Oct 16, 2013.