Ethnic minority graduates in Britain are much less likely to be employed than their white peers six months after graduation – and many can expect to earn less for years afterwards.

This dramatic divergence in life chances is revealed in a major study – the first comparison of how university choices, parental background and social class can affect students’ chances of finding jobs and fulfilling their earnings potential.

The study, by the Institute for Social and Economic Research at the University of Essex, finds that British ethnic minority graduates are between 5% and 15% less likely to be employed than their white British peers six months after graduation. There are also marked disparities in wages between many ethnic minority women and black Caribbean men who do manage to find jobs after graduation and their white counterparts.

It is a gulf that persists long after graduation, according to the study. It found that, three-and-a-half years after they left university, the difference between earnings for ethnic minorities, especially women, and their white peers increases, suggesting they may be finding it harder to climb the career ladder.

The study examined data from the Destination of Leavers of Higher Education survey, conducted by the Higher Education Statistics Agency, and found that ethnic minority graduates were less likely to be employed than white British graduates from similar socioeconomic backgrounds who grew up with similar opportunities and had similar qualifications.

The findings raise troubling questions because most ethnic minority groups in Britain are highly educated on average and are more likely to attend university than white Britons. However, they struggle to build careers. It is a concern recognised by Karen Blackett, the chair of media agency MediaCom, who graduated from Portsmouth University and in 2014 became the first woman to top the Powerlist 100 of most influential black Britons. “Stats show that one in four kids at primary schools are from a black and minority ethnic population, yet only one in eight go into employment,” she told the Daily Telegraph in 2014. “Something has to be done. That’s not right.”

The study’s authors, Wouter Zwysen and Simonetta Longhi, say the inability of ethnic minority graduates to find jobs after graduation will have serious consequences for their earnings potential later in life.

According to their research, students who are unemployed following graduation can expect to earn between 20% and 25% less later in life than those who find jobs after leaving university.

They found wide variations among different ethnic minority groups and that the pay gaps were larger for women than men. Straight after graduation, Pakistani, Bangladeshi and Chinese graduates were between 10% and 15% less likely to be employed than white British graduates. Three-and-a-half years after graduation, Chinese students were no longer at a disadvantage compared with their white counterparts.

“Six months after graduation, ethnic minority graduates are on average significantly less likely to be employed than white British graduates,” Zwysen said. “The employment gaps are slightly larger for women than for men, although the patterns are the same. Black Caribbean graduates face the smallest gap of around 3-4% and Pakistani and Bangladeshi graduates the largest gap, as they are 10% to 15% less likely to be employed than white British graduates. At three-and-a-half years after graduation, we still find employment gaps, although they are smaller. Among women all groups – except for Bangladeshi and Chinese – are significantly less likely to be employed. For men, the largest gaps are for black African graduates, who are still 9% less likely to be employed than white British graduates.”

In terms of earnings, black Caribbean, Pakistani and Bangladeshi women were at the greatest disadvantage and could expect to earn between 3% and 7% less than white British women from similar backgrounds with similar qualifications. Three-and-a-half years after graduation, the disparity in earnings between the two groups had stretched to almost 10%.

Zwysen added: “Three-and-a-half years after graduation, ethnic minority female graduates – with the exception of Chinese and Indian graduates – are earning 12% to 15% less than white British graduates, while black Caribbean and black African male graduates earn 19% and 12% less than white British graduates.”