The proportion of university students in England awarded first class degrees has continued to rise, increasing by 88% in the last eight years, the higher education watchdog has found.

Analysis from the Office for Students (OfS) found that the proportion of graduates who attained top degrees rose from 15.7% in 2010-11 to 29.5% in 2018-19, prompting concerns about grade inflation.

Much of the increase cannot be explained by changes in the characteristics of graduating cohorts, such as better prior attainment, the report said.

Over 42,000 more students graduated with firsts in the summer of 2018-19 than eight years before, the figures showed, but the increase has “slowed” compared with previous years.

Between 2017-18 and 2018-19, the proportion of firsts only rose by 0.2 percentage points, the data showed.

Ministers and the higher education watchdog have repeatedly called on universities to clamp down on grade inflation.

The data shows there has been a fall of 2.1 percentage points since 2017-18 in the proportion of students awarded the two top grades despite beginning university with grades below three Ds at A-level.

But students entering university with grades below DDD were still almost four times as likely to receive a first class degree in 2018-19 than in 2010-11.

The report concluded: “There is still strong evidence of significant unexplained sector attainment increases between 2010-11 and 2018-19.”

Nearly three-quarters (73%) of the 147 providers included in the analysis saw “unexplained” increases in first class degrees between 2017-18 and 2018-19, the analysis found.

Overall, 29.5% of students graduated in the summer of 2019 with a first class degree but, of that figure, nearly half (14.3 percentage points) of it could not be explained by changes in the graduate population.

Some institutions gave firsts to more than 40% of graduating students in 2018-19, including Imperial College London and University College London (UCL), according to the analysis.

It shows the changes in students awarded first class degrees between 2010-11 and 2018-19.

Some of the universities with significant changes include:

– Anglia Ruskin University from 14.5% to 36.7%– University of Northumbria: 16% to 36.7%– University of Bradford: 10.8% to 35.1%– Kingston University: 14.6% to 33.6%– University of Central Lancashire: 10.4% to 32.1%– University of Wolverhampton: 10.9% to 32%

Nicola Dandridge, chief executive of the OfS, said: “This data shows that the increase in the proportion of first class degrees awarded in 2018-19 has slowed compared to previous years, with a small increase from last year in the percentage of first class degrees which cannot be explained by other factors.

“While this may indicate that the brakes have been applied, it is clear that grade inflation remains a significant and pressing issue in English higher education.

“Unexplained grade inflation risks undermining public confidence in higher education, and devaluing the hard work of students. Degrees must stand the test of time, which is why the OfS will continue to address this issue at both a sector-wide and individual university level.

“Where we have concerns about unexplained grade inflation at any particular university or college, we are prepared to intervene to protect the integrity of the degree awarding system for all students.”

A Universities UK (UUK) spokesman said: “It is essential that degree classifications are meaningful for students and employers, and universities are taking action to improve transparency, fairness and reliability in the way they award degrees.

“In July 2020 universities across the UK agreed a new set of principles for degree algorithm design, having overwhelmingly supported a sector-wide statement of intent on tackling grade inflation in May 2019.

“We will be publishing a review of progress later this year exploring whether further action is needed.”

A Department for Education (DfE) spokeswoman said: “The UK has a world-class reputation for higher education and it is vital that neither low-quality degrees nor grade inflation undermine standards.

“It is unacceptable that the proportion of firsts continues to rise, despite repeated calls for action.

“Awarding powers should be used responsibly and we expect the Office for Students to take action where this is not the case.”