Grocery spending was down 1.6% overall in the most recent four weeks, the latest Nielsen data showed. Nielsen described the fall as “significant”, but said the comparative period last year had been a “bumper” time for grocers, helped by a heatwave and the royal wedding.

This year’s anniversary celebrations by Sainsbury’s and Tesco, respectively 150 and 100 years old, contributed to a rise in promotions across the sector to account for 27% of sales.