Supermarket giant Asda saw sales fall in the first six months of the year, in what's been blamed on "uncertainty surrounding Brexit".
Sales fell 0.3%, even though second-quarter sales rose after being boosted by Easter and the heatwave.
Asda boss Roger Burnley said consumer confidence was at a six-year low, "due in no small part to the ongoing uncertainty around Brexit".
In April, the competition watchdog blocked its merger with Sainsbury's.
Since the Competition and Markets Authority halted that deal, Asda's parent company, Walmart, has said the supermarket business could eventually be listed on the stock market.
Chief executive and president Roger Burnley said: "If ever a case study on the impact the mood of the nation has on UK spending habits were needed, this quarter has provided it.
"Consumer confidence levels are at an almost six-year low - due in no small part to the ongoing uncertainty around Brexit and amplified by the impact of weather and tracking against national sporting events in the same period last year.
"As a result our non-food business has been challenged during the period, however we're satisfied that our food business has continued to perform well and our online growth continues to outpace the market."
During the period, Asda spent £22 million on refurbishing nine stores and rolled out a Scan and Go mobile option to 25 stores.
The results come less than 24-hours after a group of Asda workers staged a protest in Leeds over the retailer's latest working terms.
Workers claim the grocer is threatening to dismiss them if they refuse to sign "punitive" new contracts which include giving up bank holidays.
Others told the Mirror the new so-called 'flexible' contract 6 will leave them trapped and feeling like "prisoners".
Asda said that under the new contracts, workers will not be paid for any breaks and will have to work on bank holidays and weekends - however all staff will get a £9 an hour pay rise.
