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Senior minister Michael Gove has said he does not think face coverings should be compulsory in shops in England, saying he trusts people's common sense.
It is understood ministers are considering whether to make mask use mandatory in shops and sources say the issue is being kept under review.
Speaking to the BBC's Andrew Marr, Mr Gove said wearing a mask in a shop was "basic good manners".
His comments follow calls for clarity from the government on face coverings.
Currently, face coverings are compulsory on public transport in England, Scotland and Northern Ireland to help stop the spread of coronavirus.
In Scotland, they are also mandatory in shops. Wales recommends masks but they are not compulsory.
However, there have been calls for the UK government to make its stance on masks clearer, following comments from Prime Minister Boris Johnson on Friday.
Mr Johnson - who was pictured wearing a mask for the first time during a visit to his constituency - said: "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."
Image copyright No 10 Image caption Boris Johnson wore a mask for the first time as he visited a shop in Uxbridge on FridayAsked about the issue on the BBC's Andrew Marr Show, Mr Gove said: "I don't think mandatory, no, but I would encourage people to wear face masks when they are inside, in an environment where they are likely to be mixing with others and where the ventilation may not be as good as it might.
"I think that it is basic good manners, courtesy and consideration, to wear a face mask if you are, for example, in a shop."
The Cabinet Office minister added: "Now of course the government at all times does look at the emerging evidence about what the best way to control the disease is.
"If necessary, and if tough measures are required and as we have seen in Leicester, obviously a very different situation, then tough measures will be taken.
"But on the whole... it's always best to trust people's common sense."
He earlier told Sky's Sophy Ridge On Sunday that wearing a face covering "definitely helps you to help others in an enclosed space". He also urged people to return to work rather than stay at home.
Shadow Cabinet Office minister Rachel Reeves said Labour would support mandatory face coverings for shops, as it "would inspire greater confidence and might encourage more people to go out and spend money".
"I think people are increasingly wearing them but I think some greater clarity from government about that, I think, would be helpful," she said.
"People want to do the right thing but they want to know what the right thing is. We already have it on public transport."
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Senior government sources have previously said that while no decision has yet been made on face masks, it is an issue that is being kept under review.
In the early days of the pandemic, the UK government was hesitant about advising people to wear face coverings, arguing the scientific evidence that they reduce transmission was "weak".
In early June, the World Health Organization changed its advice to say people should wear face coverings in public where social distancing is not possible. The WHO originally said there was not enough evidence to say that healthy people should wear masks.
Rules compelling people to wear face masks on public transport in England were introduced on 15 June.
A further 148 deaths were recorded in the UK, according to latest government figures on Saturday, bringing the total number of recorded deaths of people who have tested positive for coronavirus to 44,798.