Chief executives of Tesco, Sainsbury’s, Asda, Iceland, Co-Op and Marks & Spencer have written to Cabinet Office Minister Michael Gove.
Morrisons, Tesco and Asda have all said customers who don't have a reasonable explanation for not wearing a mask will be barred from shopping in their stores.
Supermarkets were the most common location reported by people testing positive for Covid-19, new data shows.