LONDON — Since the start of the coronavirus pandemic, many countries have introduced laws forcing people to wear face masks and coverings in public places in an effort to stop the spread of the virus.

While for some, face masks are not unusual and have been adopted without complaint, a vocal minority have railed against what they see as an imposition on their personal freedom. Proponents of face coverings cite studies that prove they prevent the spread of Covid-19 and so potentially save lives.

Now, as countries loosen restrictions, the wearing of face masks — or not — looks set to remain just as contentious an issue.

The debate over mask wearing heated up in England Monday after the British government announced that it would become a matter of “personal responsibility” rather than a legal requirement once Covid restrictions are removed, as planned, on July 19.

The move immediately provoked a strong response from people on both sides of the divide, who soon took to Twitter to share their views.

On Tuesday morning, the #WearAMask hashtag was trending on the social media site with debate raging between members of parliament, medical professionals and the public over whether they will (or rather, should) wear a face covering after restrictions end.

Currently, face masks or coverings must be worn in all public indoor settings in England, such as stores, supermarkets, theaters, museums and on public transport unless an individual is exempt for medical reasons. British police have the power to fine anyone £200 ($277) for not wearing a mask.

The U.K. government’s plans to lift rules on mask-wearing was widely praised by Conservative Party lawmakers, particularly those who have vehemently opposed the strict Covid restrictions, given the impact on the economy and livelihoods.

The Conservative MP for New Forest West, Desmond Swayne, was among those who voiced his support for the plan, telling CNBC Tuesday that he believed the case for mask wearing in order to prevent the spread of disease was “at best marginal” and that they had been used more as a way to induce “public reassurance and control.”

“They [masks] have significant social and psychological downsides,” he added. “It always struck me as quite incredible in a free society that we should be instructed about what to wear and fined for not doing so. Their status from 19 July is the right one: a matter of personal choice.”

Swayne, and others who see the imposition of masks as an affront to civil liberties, represent one side of the debate, and protests have been held in Britain against Covid measures, including mask wearing.

But there are plenty on the other side of the debate, arguing that it’s a civic duty to wear a mask and stop the spread of a virus that has now killed over 3.9 million people worldwide, according to data from Johns Hopkins University.

Following the U.K. government’s announcement on Monday, trade union Unite, the opposition Labour Party and some health experts were quick to voice concern or to criticize the plan, saying it is risky at a time when the delta variant is causing a surge in Covid cases, both in England and beyond.

Unite, which represents many public transport workers, said removing face coverings as a requirement would be “an act of gross negligence by the government,” and Keir Starmer, leader of the Labour party, described the move as “reckless.” Some businesses have already come out saying that face masks will still be a requirement for customers, such as airlines Ryanair and easyJet.

England is, of course, not alone when it comes to the public debate over face masks, with the U.S. seeing a similar divide. Unlike in England, however, the rules diverge from state to state in the U.S. In some states, masks are mandatory, in others, states follow the latest guidance from the U.S. Centers for Disease Control and Prevention.

In May, the CDC stated that fully vaccinated people no longer needed to wear a face mask or stay six feet away from others in most settings, whether outdoors or indoors, although it noted some nuances to the guidance (i.e. in a health-care setting or at a business that requires them).

The CDC also noted that fully vaccinated people would still need to wear masks on airplanes, buses, trains and other public transportation.

However, in June, the World Health Organization urged fully vaccinated people to continue to wear masks as the highly contagious delta variant spread rapidly across the globe.

“People cannot feel safe just because they had the two doses. They still need to protect themselves,” Dr. Mariangela Simao, WHO assistant director-general for access to medicines and health products, said, adding that a “vaccine alone won’t stop community transmission.”

Health experts, particularly those advising the U.K. government, have arguably been put in a difficult position when it comes to mask wearing.

While the U.K.’s vaccination drive has helped to break the link between infections and hospitalizations and deaths, cases are surging in younger and not-yet-fully vaccinated age groups, prompting the government to speed up the final leg of vaccinations for all U.K. adults. On Monday, over 27,000 new Covid cases were recorded, bringing the total number of infections confirmed in the U.K. to over 4.9 million.

Asked at the government’s press conference whether they would continue to wear masks themselves, medical experts advising Prime Minister Boris Johnson said they would in certain circumstances.

“The first is in any situation which is indoors and crowded, or indoors with close proximity to other people. And that is because masks help protect other people,” England’s Chief Medical Officer Chris Whitty said.

He added that “the second situation is if I was required to by any competent authority … And the third reason is if someone else was uncomfortable if I did not wear a mask – as a point of common courtesy.”

And what about Johnson? Asked whether he would continue to wear a mask when restrictions are lifted (a final decision on this will be made on July 12) he said “it will depend on the circumstances.”

“Clearly there’s a big difference between traveling on a crowded Tube train and sitting late at night in a virtually empty carriage on the main railway line,” Johnson said.

“We want people to exercise their personal responsibility but remember the value of face coverings both in protecting themselves and others.