The RBS banking group has apologised to its millions of customers after a technical problem left them unable to access accounts or withdraw money for the second time in nine months.
It came after a computer meltdown last June left millions of customers unable to withdraw cash for up to a week.
Customers began reporting problems with cash machines and cards being declined, as well as accessing their accounts online and via telephone, last night.
RBS and its subsidiaries NatWest and the Bank of Ulster initially issued apologies about the inconvenience on Twitter at 11.30pm.
The problem was later resolved at around 1am.
The technical glitches came after Sir Mervyn King dismissed the Royal Bank of Scotland's turnaround strategy as "a nonsense" and called for the bank to be split in two to make it easier to sell and recoup tax-payers money.
Sir Mervyn favours splitting the bank into two parts, a 'good' bank and a 'bad' bank, which will hold all of RBS's assets that are likely to generate continuing losses. The restructuring would allow the government to repackage the good bank and sell it off at a profit, returning the tax-payers money in the process.
Some Twitter users saw the plan differently after being unable to withdraw cash, with one person tweeting:
A spokeswoman for RBS said: "We are disappointed that our customers have faced disruption to banking services for a period this evening, and apologise for that. All services are now running as normal again."
She added that any customers having continued difficulties should contact customer services.
RBS was unable to give details about why the service was affected and whether it stopped payments and direct debits being paid.
Customers complained on social media site Twitter about being unable to access their money.
Charlie O'Brien tweeted: "Yep my card just got declined. Not able to use cash points or online banking #natwest not good at all ....."
She later added: "I had to get my info from twitter! No details anywhere else about whole system being down. Poor show."
Stephen Hester, the chief executive of RBS, which is 80% state-owned, was forced to apologise last June after millions of customers were left unable to view an up-to-date balance following a software update.
It also affected payments such as direct debits for bills and some wages were not received.