Tesco was this morning forced to close a number of its stores after a “routine IT upgrade” stopped tills from working at 100 stores.
A technical glitch brought down checkouts in affected branches today, as Tesco launched a major loyalty scheme promotion in national newspapers to its millions of Clubcard holders.
Stores were affected as they opened at 8 o’clock this morning, when the tills began to malfunction and stopped cashiers from being able to take customers’ payments, a Tesco spokesperson told Computerworld UK.
A number of stores had to be closed, while others relied on self-service checkouts which still functioned but caused lengthy queues.
Tesco began to fix the problem around midday but some stores are still affected.
Stores were unable to take payments in central London, Birmingham, Liverpool, Kent, Shropshire, Hertfordshire, Cumbria, Worcestershire, Buckinghamshire, North Wales, and Northern Ireland, according to the Press Association.
Tesco, which has more than 2,000 stores in the UK, declined to comment on what technology was affected, but said it had to resort to asking store managers to reboot tills.
"A number of stores were affected by a routine IT upgrade this morning at various locations in the country,” said a Tesco spokesperson.
“Our experts are fixing the problem as we speak ... we are very sorry for the delay and thank customers for their patience."
Ivano Ortis, retail analyst at IDC, said he was “surprised” at the extent of the problem. But he said system issues regularly occurred in store chains when complex promotions are launched, because of the extra stress on systems - both through added functionality and the extra load of customers.
“One of the key things all stores need at these times is real stress testing,” he said. “Another is to make sure that there’s the necessary redundancy in network connections and with payment providers, so that if one connection fails there are others in place.”
Another problem was that while supermarket chains often push out a standard IT infrastructure as far as possible, legacy local systems – particularly in tills – still exist in some of their stores. "This kind of problem tends to happen where there are legacy systems in place," he said.
Graham Titterington, principal analyst at Ovum, said: "The moral is that you have to test system upgrades. You need to test for the maximum expected load. And for any functionality changes, you need to fully check how systems are affected."
Last June, Tesco rival Sainsbury's was unable to trade online for two days after in-store IT problems stopped it from being able to process orders for delivery.