Rank-and-file police officers are urging shops to refuse entry to people not wearing face coverings after some high street chains said they will not penalise customers who fail to do so.
Police can hand out £100 fines to people in shops, shopping centres, banks, takeaways, post offices, sandwich shops and supermarkets in England who flout the rules.
But John Apter, the national chairman of the Police Federation of England and Wales, said forces “do not have the resources” to widely enforce the law that came into force on Friday.
He said: “It is our members who are expected to police what is a new way of living and I would urge retail outlets to play their part in making the rules crystal clear – if you are not wearing a face covering then you are not coming in.
“Officers will be there to help stores if needed – but only as a last resort, as we simply do not have the resources.
“The vast majority of the public have complied with the lockdown rules so far and I would hope they will continue to do the right thing and wear face coverings in stores to help protect fellow citizens to minimise the spread of the virus.”
Guidance was finally issued by the Government on Thursday after weeks of confusion and mixed messaging from ministers.
It states that staff in premises where face coverings are required are encouraged to “take reasonable steps to promote compliance with the law” and can refuse entry to people who do not have a valid exemption under the rules.
Retail and trade organisations criticised the Government for taking so long to publish the new laws and guidance, having announced the measure more than a week ago.
And union leaders voiced fears the rules could put workers’ safety at risk if there are abusive customers or people who refuse to wear a mask.
Tom Ironside, director of business and regulation at the British Retail Consortium trade association, said the role of retailers is to “remind and encourage compliance”.
“Where the rules aren’t being followed enforcement will be a matter for police,” he said.
“We expect and hope this will only apply in a small minority of cases.
“What’s very clear is enforcement is not a matter for retailers, that has to be a matter for the police because otherwise you will be asking staff in stores to do things which can add to the potential for conflict.”
Costa Coffee said it would “not be challenging customers” who are not wearing a mask “since they may have a legitimate reason as to why they are unable to wear one”.
Sainsbury’s said that while it is asking everyone to continue “playing their part” in helping to keep everyone safe in store by following the rules, “our colleagues will not be responsible for enforcing them”.
Asda said it will “strongly encourage customers to wear a face covering” but added: “It is the responsibility of the relevant authorities to police and enforce the new rules.”
Tesco will be selling face coverings at the entrance and Waitrose said staff would be at the entrance to stores reminding customers of the requirement.
McDonald’s said takeaway customers will need to wear face coverings but those who eat in the restaurant will not unless they are moving around the premises, for example to use toilets or when at self-order screens.
Venues like restaurants, pubs, gyms, hairdressers, beauty salons, leisure centres, cinemas, concert halls and theatres are exempt from the new rules.
Other exemptions to face coverings include children under 11, people with breathing problems and anyone who cannot put on, wear or remove a face covering because of a physical or mental illness or impairment or disability.
The guidance states that people should “assume” it is standard to wear a face covering when visiting a hospital, GP, care home or other primary or community healthcare setting.
The British Medical Association said while the guidance is helpful, it has come late in the day.
Dr Chaand Nagpaul, the association’s council chairman, said the measures were “long overdue” and added “the uncertainty of recent weeks has done nothing to inspire public confidence”.
He warned the virus “does not discriminate between buildings” and said there must be “an absolute assurance” that other mitigating measures are in place at those sites, such as screens and physical distancing.
Last week police chiefs were blindsided by the Government’s announcement after they were not told in advance of the plans and some police chiefs warned there are not the resources to patrol the aisles.
Metropolitan Police Commissioner Dame Cressida Dick said she hoped shoppers who refuse to wear masks would be “shamed” into compliance.
The Government said the responsibility for wearing a face covering “sits with individuals”, adding: “Businesses are encouraged to take reasonable steps to encourage customers to follow the law, including through signs and providing other information in store.”
The Prime Minister’s official spokesman told reporters on Thursday: “With shops, we would expect them to give advice to customers and remind them that they should be wearing a face covering and I’m sure the overwhelming majority of the public will do so.”
The laws could be in place until at least January, and even last a year, unless the Government decides to scrap them in the meantime.
Face coverings are already mandatory in shops in Scotland and will be compulsory in shops in Northern Ireland from August 1. There are no plans to make them compulsory in shops in Wales.