Boris Johnson has said people in England “should be wearing” face masks inside shops to help prevent the spread of coronavirus.
The prime minister said the government would decide in the next few days if “tools of enforcement” were needed.
The comments follow cabinet minister Michael Gove telling the BBC on Sunday that face coverings should not become mandatory in shops in England.
But he said wearing them was “basic good manners”.
Currently, face coverings are compulsory on public transport in England, Scotland and Northern Ireland.
In Scotland, they are also mandatory in shops, while Wales recommends masks but they are not compulsory.
Labour and others have complained that the situation in England’s shops remains unclear.
Visiting ambulance staff in central London, Mr Johnson, whose government controls health policy in England but not the rest of the UK, said: “I think people should be wearing [face masks] in shops.
“And, in terms of how we do that whether we make it mandatory or not, we’ll be looking at the guidance – we’ll be seeing a little bit more in the next few days.”
Mr Johnson added: “Throughout this crisis people have shown amazing sensitivity towards other people and understanding of the needs to get the virus down by doing things cooperatively.
“Wearing masks is one of them… It’s a mutual thing; people do see the value of it. We’ll be looking in the next few days about exactly how – with what tools of enforcement – we think we want to make progress.”
‘Courtesy and consideration’
Face coverings are worn to help prevent wearers spreading coronavirus.
The prime minister said on Friday: “I do think we need to be stricter in insisting people wear face coverings in confined spaces where they are meeting people they don’t normally meet.”
But on Sunday, Cabinet Office minister Mr Gove told the BBC’s Andrew Marr Show he did not think wearing masks in shops in England should be compulsory, adding that he would “encourage” them to do so “where they are likely to be mixing with others and where the ventilation may not be as good as it might”.
He added: “I think that it is basic good manners, courtesy and consideration, to wear a face mask if you are, for example, in a shop.”
Asked on BBC Radio 4’s Today programme on Monday whether he was in the “mandatory perhaps” or “mandatory never” camp, Justice Secretary Robert Buckland said: “I think I’m ‘mandatory perhaps’.
“Wearing them in an enclosed space where you’ve got lots of people, for example a busy shop, seems to be sensible.”
Speaking on BBC One’s Breakfast Mr Buckland said Mr Gove had not been “saying that people should not wear masks or take any mitigating actions at all. It’s clearly the case that wearing a mask is an act of altruism.
“It doesn’t actually protect you from he disease, but it prevents inadvertent transmission by the wearer to somebody else.”
He said he wore them himself when visiting small shops, and it was “very sensible” to do so in supermarkets at busy times.
Shadow Cabinet Office minister Rachel Reeves has said Labour will support mandatory face coverings for shops, calling for “greater clarity from government about that”.
She added: “People want to do the right thing but they want to know what the right thing is.”