Shoppers must wear face coverings in supermarkets and other shops in England from 24 July, the prime minister has announced.
Failure to follow the new rules will lead to a fine of up to £100, which will reduce to £50 if paid promptly.
Enforcement of the new compulsory policy will fall on police, but shopworkers are also expected to encourage the policy, according to No 10.
The move comes after a weekend of apparent contradictions from the government, with Boris Johnson, who was pictured wearing a face mask for the first time last week, raising the possibility of a “stricter” insistence on face covering in confined spaces. Michael Gove then told The Andrew Marr Show on Sunday it would not be mandatory.
Wearing face masks in shops is already mandatory in Scotland and coverings have also been required on public transport in England since 12 June.
A No 10 spokesman said: “There is growing evidence that wearing a face covering in an enclosed space helps protect individuals and those around them from coronavirus.
“The prime minister has been clear that people should be wearing face coverings in shops and we will make this mandatory from 24 July.”
Helen Dickinson, CEO of the British Retail Consortium, welcomed the move to protect public health and said she hoped it would make shoppers more confident about returning to the high street.
But she cautioned that shopworkers should not bear the brunt of enforcement.
“While retailers will play their part in communicating the new rules on face coverings, they must not be the ones enforcing these rules,” Dickinson said.
“With hundreds of incidents of violence and abuse directed at retail staff every day, we welcome the announcement that enforcement will be left to the authorities, rather than potentially putting hard-working retail colleagues in harm’s way. We look forward to further clarity over whether the wearing of face coverings will apply to shop staff. If so, there must be flexibility for colleagues who are in stores all day and can already benefit from other safety measures such as protective screens and two-metre distancing.”