Tesco has joined Asda, Sainsbury's and Morrisons by deciding to prevent shoppers who won't wear a face mask from entering its supermarkets.

The company will also deploy extra security to assist store managers.

The supermarket chain made the announcement amid increasing concern that social distancing measures are not being taken seriously enough in its stores.

A Tesco spokesman said: "Since the start of the pandemic, we have focused on ensuring everyone can get the food they need in a safe environment.

"To protect our customers and colleagues, we won't let anyone into our stores who is not wearing a face covering, unless they are exempt in line with Government guidance.

"We are also asking our customers to shop alone, unless they're a carer or with children. To support our colleagues, we will have additional security in stores to help manage this.

"Our colleagues are working hard in difficult circumstances to make sure everyone can get what they need, and we'd ask everyone to please be kind, patient and respectful as we all work to keep each other safe."

Earlier, vaccines minister Nadhim Zahawi said the government is worried supermarkets have become places where the virus could be spread more easily.

He said: "We are concerned that, for example, in supermarkets we need to make sure people actually wear masks and follow the one-way rule in supermarkets.

"And, of course, when they are at capacity - to operate safely, people wait outside supermarkets.

"We don't want to go any tougher, because this is a pretty tough lockdown."

Experience suggests this move will not be difficult to enforce in Heswall Tesco - it is very rare to see a shopper there without a face covering.

However, the context is sobering: the latest available figures reveal that the largest increases in COVID-19 cases are now in Liverpool City Region and the West Midlands.

There are now more than 3,000 infected people in Wirral.