Face masks will become mandatory in shops across England, ministers are to announce on Tuesday, following mixed messages, a cabinet split and mounting pressure on Boris Johnson to change public advice. New legislation will not come into force until Friday 24 July, however, raising concerns over the risk of coronavirus spreading over the next 10 days as lockdown is eased. Enforcement, which will include a fine of up to £100 for non-compliance, will be down to police, though shop staff will be expected to encourage the policy, No 10 said. The announcement is understood to have been rushed forward after Michael Gove, the cabinet minister, said on Sunday that masks should not be made mandatory, contradicting indications from the prime minister last week. It comes more than a week after Nicola Sturgeon, the Scottish first minister, announced face coverings would be compulsory in shops in Scotland, which came into force on Friday. In England, masks will be mandatory in supermarkets and all other shops, with other locations kept under review. The government had come under increased public pressure to go further on face coverings amid mounting evidence that masks can effectively hinder transmission of the virus. They were made mandatory on public transport in England on 15 June. Britons have been among the slowest to embrace mass mask-wearing. Many European countries, including Germany, Spain, Italy and Greece, have already made it compulsory to wear face coverings inside shops. A YouGov poll found that 36% of people in the UK wear a face mask in public places, compared with 86% in Spain, 83% in Italy, 78% in France and 65% in Germany. Johnson himself wore a mask for the first time in public last week, and went further on Monday, urging the public in England to wear masks in shops as “extra insurance” against the coronavirus. On a visit to the London ambulance service, he said: “The scientific evidence of face coverings, and the importance of stopping aerosol droplets; that’s been growing. So I do think that in shops it is very important to wear a face covering.” Just 24 hours before Johnson’s appearance in his distinctive blue mask on Friday, the chancellor, Rishi Sunak, sparked criticism from scientists as he posed serving diners in a Wagamama restaurant without wearing a face covering. On Sunday, Gove said he did not favour masks becoming mandatory. Government sources suggested he had misspoken and had been contrite in private. The health secretary, Matt Hancock, is expected to lay out the measures for mandatory face covering, which he is said to favour, when he addresses the House of Commons on Tuesday. “There is growing evidence that wearing a face covering in an enclosed space helps protect individuals and those around them from Coronavirus,” a No 10 spokesman said. “The prime minister has been clear that people should be wearing face coverings in shops and we will make this mandatory from 24 July.” Labour’s Jonathan Ashworth said the response had been “slow and muddled again” and said he would demand answers over why the delay to the change would be so lengthy. The shadow health secretary said: “Given the government’s own guidance issued on 11 May advised in favour of face masks, many will ask why yet again have ministers been slow in making a decision in this pandemic, and why it’ll take another 11 days before these new guidelines come into force,” he said. “The health secretary must account for this further delay.” Government sources defended the lengthy delay to the change, saying it was necessary to allow shops time to prepare and to pass the relevant legislation. Downing Street pointed to emerging evidence highlighted by the World Health Organization on airborne transmission of the virus as one of the key factors behind the changing advice. The Independent Sage group, a committee of scientists set up to scrutinise the government’s advice and led by the government’s former chief scientific adviser, Sir David King, said evidence had been growing for legislation to mandate mask-wearing. However, the group said it was “essential that masks are not seen as a panacea and other measures such as rigorous hand washing and social distancing are still stringently followed”. Wales has made three-layer face coverings mandatory on public transport from 27 July but the Welsh first minister, Mark Drakeford, stopped short of requiring masks in other public spaces, though he said their use was recommended. Face masks became compulsory on public transport on Friday in Northern Ireland, with Stormont set to review their use in other spaces. Downing Street is also poised to change the guidance about working from home as the prime minister sought to clear up confusion about whether the government is encouraging the public to return to the workplace. In his “people’s PMQs” session on Friday, Johnson had said people should be returning to work, but official government guidance continues to say, “stay at home as much as possible”. Johnson’s spokesman said that was “under review”. Johnson said more people should be returning to work but only where changes have been made to ensure their workplace is safe. “People have gone to huge lengths to make their businesses Covid-secure: so they’re installing washing facilities, they’re installing screens, they’re installing social distancing measures – doing all sorts of things to make the workplace safe,” he said. “And what I want to see is people now who have been working from home for a long time, talking to employers, talking to their place of work about the steps that have been taken, and looking to come back to work in a safe way – and that’s got to be the key thing.” Police sources said officers would expect to follow the same approach taken to enforce coronavirus restrictions on movements, of educating and explaining the need for compliance before issuing fines. Three sources said police had not been formally consulted and forces were hoping for any law to be clear. The British Chamber of Commerce said retailers would want to see the evidence between the change. Claire Walker, its co-executive director, said: “Businesses need clarity on the approach to the wearing of face coverings that is consistent and supported by public health evidence.” Face masks around the world After much to-ing and fro-ing, face coverings are finally becoming mandatory in shops in England. But in some countries it has been a requirement for months: 16 March Vietnam makes face masks compulsory in all public spaces including shops. 18 March Czech Republic becomes the first country in Europe to make masks mandatory in supermarkets, pharmacies and on public transport. 22 March Venezuela, all public spaces. 25 March Slovakia, all public spaces. 4 April Colombia, supermarkets and other places where social distancing of 1 metre is not possible. 6 April Austria, supermarkets. 7 April Turkey, shops or crowded public places. 13 April Cameroon, all public spaces. 27 April Most states in Germany, shops. 10 July Scotland, shops.