Total sales excluding fuel at Waitrose & Partners were down by 0.6% last week (to Saturday July 20) compared with the same week last year.
The supermarket chain’s commercial director Rupert Thomas said: “Sales of pre-packed fish, pork and lamb increased this week as customers fired up their barbecues.
“Bottles of Rosé also performed well, recording their strongest sales week on record, with our ‘25% off six bottles of wine’ promotion continuing to be hugely popular among customers.
“Last week, we launched multi-coloured packaging for our ready meals made from recycled plastic bottles and trays: a UK supermarket first that ensures our trays are more widely recyclable, while we continue to replace single-use plastic.”