Nationwide Building Society has admitted that 704,426 accounts had amounts wrongly debited twice earlier this week.

“Nationwide wishes to apologise to those customers affected by an issue which has affected some of our debit card customers,” said Jenny Groves, divisional director for customer experience at Nationwide Building Society.

“Debit card transactions made on Tuesday 24 July were processed twice and affected 704,426 accounts (once on 24 July and once on 25 July) due to human error. The error, which came to light earlier today, will be corrected tonight.

“A small number of customers will have been adversely impacted, estimated to be less than 50,000. All charges will be refunded in full and any costs associated with this error will be reimbursed in full. None of our customers will suffer financial loss as a result of this one-off error.

“We apologise once again for any inconvenience or uncertainty caused by this error.”