Three major banks affected by digital outages
RBS, NatWest and Ulster Bank are experiencing problems with their online and app platforms, with some customers also unable to access ATMs.
Since around five a.m. this morning customers of the banking group have been reporting problems with the services.
Although it initially looked like RBS-owned Natwest was the only bank affected by the glitch it later appeared to be the case across the RBS banking group.
"We are aware that customers are experiencing issues and are working to fix it,” said an RBS spokesman.
"Customers can still use ATMs and telephone banking or visit their local branch."
We’re aware of some issues on our Online and Mobile Banking services and are working hard to fix them. Telephone Banking and ATMs are available. Sorry and thanks for your patience.— NatWest (@NatWest_Help) September 21, 2018
However, some customers are also saying they are unable to use their cards at ATMs.
Customer Paul Murphy told the BBC: "This is just what you need as the weekend approaches and bills to pay."
Jess Cochrane said: "It's payday, I can't transfer my wage to the joint account all the bills come out of, I have no card and no branch near me."
RBS chief executive Ross McEwan told LBC radio that the bank did not know what was causing the problems.
"We're still working through what the issue is,” he said. "We make a lot of changes to our technology on an ongoing basis, it may be related to that, but we just don't know at this point."
The banks also experienced issues with their apps in April last year and Barclays customers were left unable to get into their online accounts for several hours on Thursday.
Earlier this year a major meltdown for TSB led to the eventual resignation of chief executive Paul Pester.
Hannah Maundrell, editor of money.co.uk said: "Banks really need to pull their socks up because this keeps happening. It's really not good enough when so many customers are being encouraged to bank online."
The Co-operative Bank and FinTech firm Cashplus have also experienced disruptions to service this week.