Santander UK is trying to recoup about $175 million (130 million pounds) that it accidentally transferred to customers on Christmas Day.
A technical error led 75,000 scheduled and one-off payments to be paid twice by the bank's system, The Times of London first reported.
A spokesperson for the bank said that the error had been identified and rectified. The bank will work to recover the duplicated transactions over the coming days, the spokesperson added.
The error affected 2,000 commercial and corporate accounts, which means many of those receiving money are employees or suppliers, who are customers of different banks, The Times reported.
Jenny, a UK resident who did not want to provide her surname, was among those affected. She told Insider that she thought she'd been paid twice.
She received her scheduled wage of 1,764.50 pounds on December 24. She then received a second payment for the same amount the next day. Both were listed as being from her employer, but when she contacted them they said they hadn't paid the money.
