LONDON — After months of equivocation over mandating face coverings to stop the spread of the coronavirus, the government of Prime Minister Boris Johnson was expected to announce on Tuesday that people in England must wear masks inside shops and supermarkets.
The reversal, set to take effect next week, would pull England into line with other European countries, like Germany and Italy, and other parts of Britain, like Scotland, which sets its own health policy and had already mandated face coverings.
Many scientists had found the months of dithering over masks in England mystifying. Unlike in the United States, where feelings about masks have often left the country divided along political lines, England’s hesitation stemmed in part from a scientific debate among government advisers about the masks’ usefulness.
As recently as late April, the government’s powerful Scientific Advisory Group for Emergencies retroactively edited the minutes of a previous meeting to emphasize that “it would be unreasonable to claim a large benefit from wearing a mask.”
The advisers’ misgivings, apparently a response to a lack of evidence from randomized controlled trials, reflected what critics have called a rigid approach to the science that has slowed England’s response to the virus since March.
“Some scientists feel that a very high level of certainty is required before advice is given for the public to undertake wearing a mask or other behaviors that would reduce disease transmission,” said Paul Edelstein, an emeritus professor at the University of Pennsylvania, who helped write an influential report to the British government encouraging face coverings this month.
Masks have been mandatory on public transportation in England since mid-June, and the government had previously encouraged the wearing of masks in enclosed spaces. But Mr. Johnson resisted wearing one himself until Friday.
As recently as this weekend, a prominent minister, Michael Gove, spoke publicly against the idea of mandating masks, saying that the practice should be treated as a matter of “courtesy and good manners.”
The government has indicated that the police, rather than shop owners, will enforce the new rules, with those who refuse facing a fine of up to 100 pounds, or $125.