NatWest has apologised to customers after its online banking and mobile app services went down during Black Friday sales for thousands of customers.
Downdetector, a website that tracks outage reports, recorded 2,500 customers were without service just after 8am on Friday.
The number dropped to below 1,000 three hours later.
The most reported problems were with the online bank services, with others also reporting issues with mobile banking.
The bank's online service for business finances, Bankline, was also down.
NatWest customers vented their frustration on social media, claiming they had been unable to make the most of Black Friday offers.
Others said they were unable to pay their bills.
NatWest, which is owned by the Royal Bank of Scotland Group, tweeted: “Our Online Banking, mobile app and Bankline are currently facing intermittent problems. We're working hard getting them back up and running smoothly for you.
“We’ll post an update when we have more information. And remember to contact us if you need urgent help.”
The RBS Group said in a statement: "We are aware that some customers are experiencing intermittent issues accessing our mobile and online banking.
"We apologise to customers for the inconvenience and are working hard to fix the problem. There is no impact on debit cards, credit cards, ATMs, telephone and branch banking services - customers can continue to access these as normal."
