In the latest departure from UK-wide coronavirus guidance, Scotland’s First Minister Nicola Sturgeon announced that coverings should be used when social distancing is hard to maintain.
The new recommendations for everyone above the age of two to wear face coverings made of cloth, including scarves, will apply on public transport and in shops.
“We are recommending that you do wear a cloth face covering if you are in an enclosed space with others where social distancing is difficult, for example public transport or in a shop,” the SNP leader said during her daily COVID-19 briefing.
Number 10 later said the UK government had not decided on its approach after receiving evidence from the scientific advisory group for emergencies (Sage) last week.
Boris Johnson’s official spokesman said that ministers were “considering the advice they have been given and once a decision has been reached then we will announce it publicly”.
Ms Sturgeon’s use of the more general term of coverings distinguishes then from the use of medical-grade masks, amid fears an increased public uptake could cause a shortage for NHS workers.
Scotland has stopped short of making their use mandatory, conceding evidence over their use was “still limited”.
But the first minister said there were benefits in wearing coverings to reduce transmission from individuals who are not yet exhibiting symptoms.
Number 10 insisted the prime minister wanted to maintain a UK-wide response as far as possible.
“There have been points in the response so far where announcements have been made at ever so slightly different times,” his spokesman said.
“By and large we have moved forward with a single four-nations approach. I think the devolved administrations in Scotland, Wales and Northern Ireland have all said they hope that continues to be the case and we would agree with that.
“We continue to work closely with them.”
Leaders across the UK have all said they want to maintain a unified response to the pandemic.
But Ms Sturgeon has warned she “will not hesitate” in taking Scotland in a different direction, while the Welsh government announced an extension to the lockdown ahead of other nations last week.
The new advice was broadly welcomed by experts, although some said officials should reveal any new evidence that had prompted the decision.
Trish Greenhalgh, professor of primary care health sciences at Oxford University Nuffield Department, said the decision was “a common-sense way of reducing the transmission”.
She said: “They are as evidence-based as school closures, handwashing and lockdown, in that none of these measures is supported by definitive randomised controlled trials but all are supported by other kinds of science.”
Ian Jones, professor of virology at the University of Reading, said the decision was in line with other European countries and was “simply, a no-brainer”.
“The arguments against mask use always centre on if they are worn appropriately, if they lead to a false sense of security or if their use will limit supplies,” he said.
“But the real scientific question is ‘can they reduce transmission’ and the answer to that is yes.”
But Keith Neal, emeritus professor of the epidemiology of infectious diseases at the University of Nottingham, suggested the decision was political and not supported by evidence.
“It is impossible to know why this has been suggested now given there has been no change in the evidence,” he said.
“The decision seems political given it is against the Scottish and other UK scientific advice that has been given. There is no indication to make this UK wide due to the lack of evidence and strong possibility that they will not work.”