Customers took to Twitter to vent their anger after many were unable to withdraw cash or transfer money online.
NatWest customer Mark Hillman had planned an evening out last night, but it was cut short when he was unable to withdraw any cash.
He said: "I went from a night out to staying in, because I couldn't get my hands on my cash."
More top news
Simon Cowell has the Overs category while Cheryl Fernandez-Versini will be mentoring the Groups.
The author of the new James Bond novel has apologised after he said that British actor Idris Elba is "too street" to play the spy.
After a bit of a nippy feel over night and an Autumnal feel into the morning.