Rising numbers of poor students are dropping out of university before finishing their degree, figures suggest.
The proportion of youngsters from disadvantaged families who do not continue after their first year at university has reached the highest level for five years, according to a report by the Office for Fair Access (Offa).
It also shows that a young person's chances of gaining at least a 2:1 depend significantly on their ethnic background.
Offa director Les Ebdon said it was a "disgrace" that a student's degree classification should be linked to their ethnicity.
The report looks at the progress universities and colleges have made in widening participation in higher education - encouraging more disadvantaged young people to study for a degree - against the commitments and targets institutions made in their 2015/16 "access agreements".
Institutions wishing to charge higher tuition fees, up to a maximum of £9,250, must sign an "access agreement" with Offa.
The report concludes: "While more disadvantaged young people are in higher education than ever before, the numbers of those students leaving before completing their studies has risen for the second year in a row."
Official data shows that in 2014/15, 8.8% of young, full-time disadvantaged undergraduates do not continue in higher education beyond their first year, up from 8.2% the year before, and the highest level since 2009/10.
In comparison, in 2014/15, less than 5% of those from the richest backgrounds did not continue their studies.
"The gap between the non-continuation rates of the most advantaged and most disadvantaged students has widened in the past year," the report says.
It adds: "The significance of this for students is huge. Higher education can be a transformational experience that opens doors to rewarding careers and social mobility, but this is only the case if students achieve successful outcomes."
The report also found the non-continuation rate for black students is almost 1.5 times higher than it is for white and Asian students.
"For black students who complete their degree, the level of attainment is also markedly different: while 76% of white students graduated with a 'good degree' (first or 2:1), only 52% of black students did the same," it adds.
Speaking ahead of the Offa report's publication, Prof Ebdon said: "If we look at outcomes that students achieve, by ethnic group, we can see that there's a 15 percentage point difference between the likelihood of obtaining a first or 2:1 if you come from a black and minority ethnic group, than if you come from a white group.
"I think it's an absolute disgrace that the class of degree that you get should depend on your ethnicity," he told a Buckingham University conference on higher education.
He later said: "It's not just about getting in, it's about getting on.
"What we want is both access and success, so I am concerned, I am concerned that universities are doing enough to support students from different backgrounds when they get into university."
The drop out rate has gone up "fractionally", Prof Ebdon said, but it is important to spot this early and address it.