LONDON (Reuters) - TSB was hit by another technology glitch on Monday, the latest since a botched IT upgrade in April resulted in one of the country's worst banking outages.
TSB chief executive Paul Pester was criticised by MPs over his handling of the crisis, which has cost its Spanish parent Sabadell more than 200 million euros (£180.3 million) and damaged TSB's reputation.
The outage, which the bank said hit online and mobile banking, prompted some customers to say they would switch banks.
"We'd like to apologise for any inconvenience this may cause," a TSB spokeswoman said, adding customers were able to use their cards as normal.
A small number of customers were affected and by the middle of the day the vast majority were able to log in as normal, she told Reuters by phone.
The spokeswoman said the problems were unconnected to planned maintenance work that took place on Friday and declined to say exactly how many of the 1.9 million customers who use TSB's digital banking services were affected.
Some took to Twitter to say that the latest problems marked the last straw after April's outage left many unable to access their accounts for days. Some specific services are still not back to normal.
"How do I complain in writing via email about you locking me out of my account again," said one customer, Maggie Morrissey, in a tweet. "This is the finish, I will switch to HSBC..."
Another customer, Matthew Nowicki, said he had not been able to see one of his accounts since April.
The bank is still just recovering after the April outage meant customers were unable to make vital payments, led to a spike in fraud and left TSB staff struggling to help.
Three senior executives are due to leave the bank in the coming months, although TSB said the departures were not related to the IT issues.
(Reporting by Emma Rumney; Editing by Alexander Smith)