Bosses at the University of Bristol have announced that stuff and students must wear face masks inside all buildings on campus, as coronavirus case numbers in the city rise again.
Everyone will have to wear a covering indoors from now on, unless they are medically exempt.
According to bosses, the decision was made because of increasing infection rates in Bristol and "extreme pressure" on the NHS.
It coincides with an announcement from health chiefs that the service faces the toughest winter in its history. Meanwhile, the Prime Minister has urged everyone to get vaccinated as their main source of protection from the virus.
A University of Bristol spokesperson said: "COVID-19 rates in Bristol remain high and above the average across most of England, and hospitalisation rates continue to put our NHS services under extreme pressure.
"While it is very reassuring that cases within our university community remain low, we are concerned that this picture could change quickly if we drop our guard during the winter months when social distancing and ventilation is more challenging and when other seasonal viruses such as flu are likely to compound the situation further."
It is not a legal requirement to wear a mask indoors but the decision will hopefully prevent students from having to return to online learning, a Bristol University spokesperson said.
The "precautionary" measure applies unless an individual is medically exempt, eating or drinking, or can keep a reasonable distance from other people.
"We realise there is currently no legal requirement to wear a face covering but are confident that now is the time to introduce this local institutional requirement," a spokesperson added.
"Students have made it very clear how much they value their in-person on-campus teaching. By acting now, we will increase the likelihood that we can continue this key element of the Bristol experience during the difficult winter months ahead."
Dr Alix Dietzel, a lecturer in Global Ethics, tweeted after the rule was made public and said she was "relieved".
"I've been teaching for a few weeks now, we're in week eight of term, and in the first couple of weeks I had maybe 90% of students wearing their masks and that has really slipped," she told ITV West Country.
"Yesterday I gave a lecture that had 100 people in the room, and I think I had three or four people wearing a mask."
Speaking at a Downing Street press conference on Monday 15 November, the Prime Minister focused on vaccines as he warned the public about a new wave of the virus.
Boris Johnson said: "If we want to control the epidemic here in the UK and if we want to avoid restrictions on our daily lives we must all get vaccinated as soon as we are eligible.”
Warning of a "new wave" sweeping through central and western Europe, he said countries with higher vaccination rates have fared better after surges in infections.
The covid vaccine booster programme is now being expanded to include healthy 40 to 49-year-olds, also in a bid to protect the NHS and keep case numbers down.