Building society Nationwide is the latest banking organisation to have been affected by an IT glitch when it admitted today double-billing two million transactions made by its current account customers on Tuesday.
The bank blamed human error for the problem and promised today that the transactions would be reversed in its payment run tonight. It also promised to reimburse customers for losses caused as a result of the glitch, some of whom have been denied access to their money as a result.
"We have identified an issue where some current account card transactions made on the 24th July [Tuesday] were duplicated on 25th July. This is a one-off, isolated incident and is down to human error. The duplicated transactions will be corrected overnight.
"We would like to apologise for the inconvenience this has caused and we can assure customers that should they incur any related charges these will be refunded in full," it said in a statement published on its website.
One customer, Leigh O'Riordan, told the BBC that he had paid for his annual rail season ticket to work at a cost of £3,422 on Tuesday – only for the payment to be made twice, plunging him into overdraft and preventing him from withdrawing more money from his account.
Another customer claimed to have bought a car at the weekend, paying £9,000 on his debit card, only to find that the payment had been taken twice, preventing him from withdrawing further funds.
However, the building society seems to have handled the issue better than the Royal Bank of Scotland (RBS), which locked out customers for up to a week last month following a botched software upgrade.
"It took me a while to get through to Nationwide, but they were very good and they apologised," O'Riordan told the BBC.
Nationwide's error comes just one month after RBS locked out 12 million customers of NatWest, Ulster Bank and Coutts & Co from their accounts for a week.
The problem prevented them from accessing their accounts online, withdrawing money at cash machines, making payments in shops or online, or transferring money to suppliers, staff and contractors.
While NatWest customers were locked out for one week, some Ulster Bank customers were affected for almost a month.