Students in England will be asked to stay at home after Christmas as part of a staggered return to university to prevent coronavirus outbreaks.
The UK government said on Thursday that students should learn online after the festive period before being allowed to return to campus over a five-week period beginning on January 4.
It means February 7 is the latest students are expected to be back at university.
Medical students and others on practical placements with a need for in-person teaching will be given priority to return between January 4 and January 18.
Other courses will be available online and students should wait for their return date, according to Department for Education guidance.
The government hopes the measure will prevent a repeat of the problems of recent months, when students were locked in their dorms after outbreaks at many universities.
Rolling lockdowns on campuses, the shift to online learning and curbs to social activities forced many international students to consider going home.
“The health and well-being of students, staff and local communities is always our primary concern and this plan will enable a safer return for all students," Universities Minister Michelle Donelan said.
“But we must do this in a way which minimises the risk of transmission. I know students have had to make sacrifices this year and have faced a number of challenges, but this staggered return will help to protect students, staff and communities.”
The guidance also said students should be offered a rapid coronavirus test regardless of whether they display symptoms.
If they test positive, they will be asked to self-isolate in their university accommodation.
Jo Grady, general secretary of the University and College Union, welcomed the move to online learning at the start of term.
"We need to see an effective test, trace and isolate programme that links university and public testing systems," she said.
"This must include co-ordinating student travel between institutions, and risk assessments on any return to campus.
“We need online learning to remain the default position for universities until these issues are fixed, otherwise we risk further spikes in virus transmission.”