An RBS and NatWest spokesperson said:
We apologise for the disruption our customers experienced last night. All systems are up and running as normal, though any customers with any individual problems should get in touch with us.
Between roughly 9-11pm customers were not able to access online banking and also had problems with ATM use and point of service payments.
This problem was caused by a hardware fault and was not related to the issues we experienced last summer. It was much easier to fix, though clearly an unacceptable failure.
Any customer who was left out of pocket due to this outage should get in touch so we can put things right for them.