Barclays said a glitch occurred in its computer system on Saturday before planned adjustments to coincide with the end of British summer time.
The bank said the work related to the clocks changing did not cause the problem but that it meant systems took longer to be restored on Sunday.
The bank said: “We can confirm that customer services are now recovering from the outage we experienced [on Saturday]. We apologise to customers for any inconvenience caused.”
Barclays tweeted around midday on Saturday that it was investigating technical problems. The bank then notified customers about the work related to the clocks changing that evening.
The bank said the problem was an internal one and was not caused by someone hacking into its computers. Concerns about companies’ cybersecurity are running high after hackers stole data about up to 4 million customers of the phone company Talk Talk.
Barclays customers reported various difficulties with their accounts, including not being able to use their debit cards or bank online.
The problem at Barclays is the latest computer failure to affect bank customers. The head of the British Bankers’ Association has said banks’ antiquated computer systems are creaking under the strain of customers moving to online and mobile banking. Royal Bank of Scotland was fined £56m for a meltdown in 2012 that left millions of customers locked out of their accounts for days.
Barclays said the problem had been fixed and asked customers to use online and digital banking services instead of calling because of large numbers of phone enquiries. Some customers complained about how the bank dealt with their enquiries and said they were still having difficulties.
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