More than 200,000 UK credit and debit card holders have been double-charged for transactions conducted on New Years Eve following a payment processing failure at Lloyds TSB Cardnet.
The snafu will have hit users of multiple banks who paid for transactions at shops and bars serviced by Lloyds' wireless Eftpos terminals.
Lloyds blames the duplicated transactions on a technical error affecting "certain payments from card holders to some merchants".
It has apologised to customers and set up a help line, urging card holders who think they may have been charged twice to contact the bank.
"We will consider all reasonable and evidenced requests for reimbursement," says the bank in a statement.