Supermarket chain Tesco has been unable to take money at a number of its stores following technical problems affecting its tills.
The till issues began on Monday morning and are likely to have been caused by routine maintenance of IT systems, a Tesco spokesperson said. The supermarket chain was unable to say exactly which of its systems and software had been hit.
"We have had a problem caused by an IT glitch," the spokesperson told ZDNet UK on Monday. "Some of our systems have gone down, and the IT guys are working ridiculously hard to get them up and running. We are nearly there now."
At the peak of the problem, checkouts at 67 of Tesco's 2,814 UK stores were not working, according to Tesco. Some stores had to close as a result.
Tesco said that all types of payments, including credit and debit cards and cash via normal tills, had been affected. However, self-service systems in affected stores and in Tesco garages had not been affected.
An investigation into the cause of the outage will be launched shortly, the spokesperson said, noting that the problem was probably caused by software updates that had been sent out on Sunday night. The issues were unlikely to have been caused by a hacking attack, the spokesperson added.
Commentators on microblogging site Twitter said that affected stores had included those in Wrexham and in Edinburgh.
Tesco's spokesperson declined to comment on how much business the company may have lost through store closures and slower queuing times, but said the impact had been minimal.
"On Monday morning, most stores are not open until 0800," said the spokesperson. "The problems started to be resolved immediately, and most stores are now back to normal."