NatWest and RBS customers were yesterday unable to bank because of technical problems that began at 6.30pm.
Customers were unable to pay for items using their credit or debit cards or use online banking and mobile phone apps.
As experts said Britain’s bank customers could face increasing technical problems due to non-performing systems and more payments online, security specialist firm also warned customers to watch out for phishing emails which appear to have been sent by their bank.
Check Point’s UK managing director Keith Bird said: "Bank customers need to be very careful not to click on links in emails which appear to come from RBS, Nat West or Ulster Bank advising them about changes to account security, no matter how authentic the email seems to be.
"Attackers have jumped at this opportunity to try and trick customers affected by yesterday’s technical problems into revealing their bank details. For those attackers, it’s just a numbers game, but it could have serious consequences for customers. Phishing emails continue to be the most common source for social engineering attacks."
