A cap on student numbers may be needed to help universities deal with the uncertainty caused by the coronavirus crisis, it has been suggested.
"Radical action" will be needed on university admissions for the "foreseeable future", according to a blog co-authored by Sir Chris Husbands, vice-chancellor of Sheffield Hallam University.
It warns that the pandemic presents "serious risks and challenges" for universities and financial stability.
Universities are currently dealing with the knock-on effect of schools and colleges closing, and the cancellation of exams.
In addition, there are concerns about the impact the worldwide outbreak of Covid-19 could have on international students - the UK is a major player in the international student market, attracting tens of thousands of people to its universities every year.
In his paper, published by the Higher Education Policy Institute (HEPI), Sir Chris sets out a series of possible measures that could help address some of the risks to universities.
Last week, the universities were told to stop making unconditional offers to students for the next fortnight, as part of an attempt to tackle confusion caused by the pandemic and uncertainty among students about how they will secure degree places.
The move came amid concerns that institutions were dropping exam requirements in an attempt to encourage students to confirm a university as their first choice.
Sir Chris says that this action is welcome, but added:
Radical action is needed on university admissions for the foreseeable future.
Sir Chris, who co-authored the paper with Natalie Day, head of policy and strategy at Sheffield Hallam University, goes on to say this means reimposing number controls to ensure that universities have a viable number of first-year students.
"Realistically, given the damage to school students' education and examination preparation, this will not be a one-year exercise," the paper says.
It also says:
The Covid-19 pandemic presents serious risks and challenges for the sector - some of them existential.
Other measures suggested by the authors include rent support for students and schemes around the retention and progression of students.