Around 600,000 bank account payments have gone missing after a technical glitch at NatWest owner Royal Bank of Scotland (RBS).
The group said an issue with its “overnight process” meant some customers of NatWest, RBS, Ulster Bank and private bank Coutts had not seen credits or direct debits applied to their accounts.
An RBS spokesman said the issue had been identified and fixed, but it was still working to retrieve missing payments.
RBS said: “We are working to get this resolved as quickly as possible and apologise to customers for the inconvenience caused.
Delayed payments would be processed “no later than Saturday”, RBS added.
“To any customers concerned about the implications of this issue we advise them to get in touch with our call centres or come into a branch where our staff will be ready to help.
“We will ensure no customers are left out of pocket as a result of this issue.”
NatWest’s Help Twitter account has been bombarded with tweets from worried customers who have woken up this morning to find payments missing from their accounts.
The group was not able to confirm how many customers had been affected, but said it was not all accounts.
NatWest and RBS have been hit by a number of embarrassing IT glitches in recent years.
In 2013, RBS’s online service was disrupted by a denial-of-service attack.
In November 2014, the state-backed group was hit with a £56 million fine from the Bank of England and City watchdog Financial Conduct Authority after a computer failure in 2012 saw as many as 6.5 million customers unable to make payments for as long as three weeks.
The outage hit customers at NatWest and Ulster Bank - RBS’s Irish business.
Guy Anker, the managing editor of MoneySavingExpert.com, said: “This is a hugely worrying time for those affected. It’s vital anyone with an RBS, NatWest, Ulster or Coutts account that was expecting money today or is expecting money to go out, say to pay a bill, checks their account immediately.”
He added: “If you were due to make important payments today such as your mortgage, rent or utility bills, then ensure you let the other person or company know as soon as possible.”