A shopworkers’ union has been “inundated” with complaints from its members, who say they are “deeply concerned” for their safety as members of the public flout in-store Covid measures.

Usdaw urged supermarkets and food retailers to revert to “stringent” restrictions and said that staff – who are classed as key workers – must be “valued, respected and protected”.

Chains such as Tesco and Sainsbury’s said safety remains their “highest priority” and that customers were given regular reminders to follow the rules.

It comes as vaccines minister Nadhim Zahawi voiced his concerns that members of the public were not complying with measures put in place by supermarkets, amid suggestions the restrictions may need to be toughened.

“I am worried about supermarkets and people actually wearing masks and following the one-way system and making sure when it’s at capacity they wait outside the supermarket,” he said.

Usdaw general secretary Paddy Lillis said: “Retail staff are working with the public every day and not only suffer increased abuse, but are deeply worried about catching Covid-19.

“Where safety measures are agreed, retailers need to make sure that they are being followed consistently, in every store.

“We are also very concerned by reports that too many customers are not following necessary safety measures like social distancing, wearing a face covering and only shopping for essential items.

“It is going to take some time to roll out the vaccine and we cannot afford to be complacent in the meantime, particularly with a new strain sweeping the nation.

“Many retail workers are at a greater risk of catching the virus and bringing it home to their families.

“Supermarket workers and delivery drivers have worked throughout the pandemic to keep the country supplied with essentials.

“These key workers must be valued, respected and protected.”

A spokeswoman for Sainsbury’s said: “Safety remains our highest priority.

“We continue to have a range of measures in place to keep customers and colleagues safe in our stores.

“We have greeters outside our supermarkets and busy convenience stores to limit the number of customers coming into stores and continue to remind customers to wear face coverings and shop alone if they are able to.

“We also have posters and regular Tannoy announcements.”

Tesco said it was still enforcing social distancing practices in store but was not looking yet at reintroducing measures such as one-way aisles.

“The safety of our customers and colleagues is our top priority and we already have extensive social distancing measures in our stores to ensure everyone can shop safely with us,” the store said on Twitter.

“We are asking all our customers to wear a face covering when visiting our stores and have prominent signs in place to inform customers of the rules.

“However, there may be some customers who are unable to wear a face covering for medical or safety reasons and we have asked our colleagues to respect that and to not challenge them directly.”

Data from Public Health England last week found 11 outbreaks of the disease had come from food outlets.

But England’s chief medical officer Professor Chris Whitty said supermarket staff would not be initially prioritised for vaccinations unless they also fell into the highest vulnerability categories.

Responding to a question from a food retail worker from Somerset on BBC Radio 5 Live, he said: “All of us in society have relied on the extraordinary work of people who have kept retail for essential goods – food and so on – going, and I think all of us should thank you and your colleagues very much for that.

“In terms of vaccination prioritisation… the initial wave is all around the people who have the highest risk of dying, it’s a clinical question, largely on age.

“Obviously if someone falls into that, if they’re an older person working in retail or they have a health condition, they will be included in that.”

Prof Whitty added that as soon as the most vulnerable were vaccinated then ministers would decide who to prioritise next.