Universities in the UK are being urged to scrap plans for face-to-face teaching until Christmas in order to prevent a second wave of coronavirus.
Academics’ union, UCU, said more than a million students moving around the country was “a recipe for disaster”.
UCU leader Jo Grady said universities were not prepared, and risked becoming the “care homes of the second wave”.
But university bosses say they have worked hard to plan for a safe return to all aspects of student life.
When the students return in September, they will be expected to abide by new policies on the use of face coverings and social distancing protocols.
Meanwhile there will be safety partitions to keep them apart, as well as more cleaning and ventilation and smaller class sizes where face-to-face teaching takes place.
When national lockdown measures were brought in at the end of March, universities cancelled lectures, tutorials and some exams. Many continued their lessons and lectures online however, and even held final exams remotely.
Over the summer, universities have been preparing for the return of their students’ return, with most promising a mix of face-to-face and online learning – or “blended learning” – with students learning in extended “bubble” groups.
But few, if any, universities have taken the step of telling their students not to move into their accommodation.
Ms Grady said having tens of thousands of students heading into cities across the UK “risks doing untold damage to people’s health and exacerbating the worst public health crisis of our lifetimes”.
She said: “We are very concerned that universities, and the UK more generally, are simply not prepared for the mass migration of what is over a million students.
“In particular, we are concerned about students going from high risk areas into areas with fewer cases.”
She said she was particularly worried about the risk of the virus spreading in cities with big student populations.
“Mrs Grady said: “If we look at some key cities: Manchester has 100,000 students; Birmingham isn’t far behind with 80,000; and Leicester has 40,000.
“These are all cities that have had some form of local lockdown and have come out of it or are about to go into one.”
She added: “We don’t have a functioning track and trace [system], we don’t have a UK-wide testing for students who are arriving for university, or subsequent and regular testing.
“We are really worried about young people congregating in halls of residence and just what this will mean in terms of transmission.
“We don’t think sufficient safety measures are in place,” she added.
The union said it was backing the position of the Independent Sage committee which has called for online learning to be universities’ default position.
The already difficult situation, with universities doing their best to bring in socially distanced ways of working, has been made worse by the higher than expected number of students this year, she said.
‘No regular testing’
The exams crisis over the summer meant many more students ultimately achieved the grades needed to get into university, after the government’s last-minute change of mind on school-assessed grades.
The UCU says there will be challenges in ditching the blended learning approach, and replacing it with online-only teaching.
But Ms Grady said it was time for the government “to finally take some decisive and responsible action in this crisis and tell universities to abandon face-to-face teaching”.
She also called on the government to underwrite any loss of fee income to universities, and to support students who have problems in connecting remotely.
National Union of Students president Larissa Kennedy said universities should only deliver face-to-face teaching for lab-based and practice-based courses.
“In-person teaching should only take place if can be delivered safely for all staff and students, and social distancing guidelines and other safety measures can be maintained,” she said.
She backed calls for more student support with remote learning and urged universities to work with their student unions on decisions about how best to re-open campuses.
Universities UK president Julia Buckingham said: “Many staff want to return to in-person teaching, research and other activities where it is safe and appropriate to do so.”
They are also mindful of the benefits of in-person teaching and support for students’ well-being and development, he said.
“The dedication shown throughout the lockdown and into recovery has been remarkable,” she added.
A Department for Education spokesman said: “We are confident that universities are well prepared for the return of students by taking measures such as introducing social distancing on campus, limiting travel requirement for classes and staggering teaching across extended days to reduce numbers on site.
“Opening universities is a part of the Prime Minister’s cautious roadmap, and it is important that we continue to open education settings wherever it is safe to do so.
“We support face to face teaching only where possible and if safety guidelines are followed, but know that high quality online teaching can also be delivered if necessary.
“We are keeping our guidance under constant review, and are currently updating our advice on reopening higher education buildings and campuses to reflect the latest public health advice, including on face coverings, local lockdowns and test and trace.”