A system crash at Barclays bank on Saturday left customers unable to access their bank accounts, withdraw funds or check their balances.
The outage affected online and telephone banking, and ATM services. A frustrated customer who did not wish to be named said: "I tried five different ATMs and couldn't get any cash, or even check my balance."
A spokesperson for the bank said: "The issue lasted for around 20 minutes before systems were restored. We apologise to customers for any inconvenience."
The bank refused to go into any details regarding the cause of the problem, or how it was resolved, but admitted that it was impossible to rule out the prospect of a similar loss of service in the future.
"We hesitate to confirm that it couldn't happen again, but customers can be reassured that we make strenuous efforts to provide a high quality of service," they said.
The spokesperson added that the crash did not affect the point of sale, as misreported elsewhere, meaning that debit cards were not affected.