Black engineering graduates are less likely to find jobs than white students with lower second or third class degrees, according to a report that reveals stark inequalities within the profession.

The review, by the Royal Academy of Engineering (RAEng), found that being black or minority ethnic was a bigger obstacle to employment than any other factor considered, including degree classification, attending a less prestigious university or gender.

Bola Fatimilehin, the academy’s head of diversity, said an old boys’ network approach to recruitment and unconscious biases were contributing to the challenges faced by non-white students.

“There is a certain amount of stereotyping of who can be an engineer and what talent looks like,” she said. “A lot of people fall into the mode of thinking that there aren’t a lot of black engineers because [black people] are not interested in it.”

The analysis found that 71% of white engineering graduates were in full-time jobs within six months of leaving university, compared with just 52% of Asian students and 46% of black students.

When gender, age, class of degree and type of institution were taken into account, black and Asian graduates were more than twice as likely to be unemployed as their white counterparts.

The figures highlight an apparent paradox in which government and industry leaders have consistently pointed to a national shortage of engineers, while a high proportion of black and ethnic minority graduates are failing to find jobs. Indeed, the science minister, Jo Johnson, noted “the chronic shortages of engineers that have long held our economy back” in a comment article last month.

The shortage of engineers is often cited as an incentive to attract more women into the profession – just 12-15% of engineering undergraduates are female.

“That’s true, but what about the missed opportunity with all these graduates from ethnic minority backgrounds?” said Fatimilehin. “It feels like a low hanging fruit.”

Gender has dominated the diversity agenda in engineering for the past decade, but the report found that it only has a minor influence on immediate employment prospects for graduates. Women were slightly less likely to enter engineering occupations after university, but more likely to pursue further study.

The focus on “getting girls into engineering” has led to the lack of progress on racial diversity being overlooked, according to Fatimilehin.

“People come back to gender because it feels safer,” she said, adding that male engineers tended to get behind the idea that women face additional barriers because most would have a wife, daughter or female friend. “They’re less likely to have a friend who is black,” she said.

The RAEng report puts forward several possible explanations for the findings, which were based annual destination surveys of around 250,000 students by the Higher Education Statistics Agency (HESA). Engineering firms often recruit from Russell Group universities, which on average have lower proportions of ethnic minority students. However, even when institution type is taken into account there is a gulf between the employment prospects of white students and black and Asian ones.

“This suggests statistically that ethnicity itself is correlated with an unemployment outcome, and is a stronger effect than any of the other factors studied,” the report concluded.

According to Fatimilehin, unconscious bias, preconceptions about who will “fit in” with company culture and people “recruiting in their own image” also play a role.

“The chief execs say ‘there’s nobody out there’,” she said. “There are people out there. As a society we need to get better at looking for people, rather than just accepting that a certain type of black person doesn’t exist.”

Anita Bernie, director of spacecraft platforms at Surrey Satellite Technology Ltd (SSTL), said she was “amazed” by the gulf in career prospects between white and ethnic minority students. Bernie, who is black, said that SSTL has a diverse mix of ethnicities and that most of her current team are female.

“When I go to other companies, the mix in terms of gender and ethnicity is very different,” she said.

Bernie agreed that employer recruitment bias is likely to be a problem. “It’s partly human nature that you tend to want to recruit people like you,” she said. “It’s really easy to see a young white lad come in and think ‘I used to be like that’. I do think that exists in other companies.”

Rebecca Hilsenrath, chief executive of the Equality and Human Rights Commission said: “It is shocking that black and minority ethnic people with degrees are still not getting the same job opportunities as others. This suggests we have a long way to go to create the equal society the prime minister talked about on the steps of Downing Street.”

An EHRC report published earlier this year found that the life prospects for young black and minority ethnic people have got much worse over the past five years and are at their most challenging for generations. On average, black, Asian and ethnic minority workers with degrees are two-and-a-half times more likely to be unemployed than white workers with degrees, the report found.

Belinda Phipps, CEO of the Science Council, welcomed the RAEng review, saying it was important to highlight inequalities in the profession. “From the moment a baby is born its life is shaped by the enforcement of stereotypes: girl children are taught they must be clean and quiet; those of certain ethnic origin are expected not to succeed,” she said.