Universities could be stripped of their powers to award degrees if they do not act to stop the steep rise of "unjustifiable" first-class qualifications, the Education Secretary has warned.

Damian Hinds is calling for an end to artificial grade inflation to protect the sector's "world-class" reputation.

He says he wants institutions to take action from the next academic year to reset the proportion of firsts and 2:1s awarded.

The Government hopes to strengthen the Office for Students' (OfS) powers this year, to allow the public body to levy fines of up to £500,000 or 2% of a university's income, whichever is higher.

Universities found to be damaging students' interests could be subject to sanctions, fines or removing powers to award degrees, the Department of Education said.

Mr Hinds said: "Our universities are world-class and world-leading, with four ranked among the top 10 in the world, and attracting thousands of international students.

"At the heart of that global reputation is a trust in the quality and high standards of the education provided.

"Unjustifiable, artificial grade inflation threatens that. It cannot be right that students in one year are awarded higher grades for the same level of achievement than those in previous years.

"We owe it to the hardworking students who have earned those top grades to stamp out this unfair practice.

"I expect the Office for Students - when they have their full range of powers - to challenge those institutions that record an unjustifiable rise in the proportion of top degrees being awarded."

The intervention comes after analysis published by the OfS in December showed 27% of students obtained a first-class degree in 2016/17, compared to 16% in 2010/11.

The analysis suggested 50.1% of students at the University of Surrey were awarded a first in 2016/17 while at the University of Huddersfield 37.9% of students were awarded a first.

Professor Dame Janet Beer, President of Universities UK, said universities are "determined" to tackle grade inflation.

"The sector's collective will to take ownership of this challenge is strong, as we recognise it is crucial that we keep the confidence of students, employers and the public in the value of a university qualification," she said.

"It is important to draw a distinction between grade inflation and grade improvement, where increased investment in teaching and facilities, as well as students working harder than ever, are leading to legitimate increases in grades."

Nicola Dandridge, chief executive of the Office for Students, said: "Students work extremely hard to earn their degrees and it is crucial that the qualifications they earn hold their value over time.

"Our own research on this issue found there has been significant and unexplained grade inflation in recent years.

"This is clearly not in the long-term interest of students and risks undermining wider public support in our higher education system."