An IT meltdown landed Royal Bank of Scotland with more big fines today after millions of its customers were left unable to access key banking services.
Penalties totalling £56 million from the UK's two financial regulators are on top of the £70 million in redress already paid to customers following the systems crash in 2012, which affected RBS and its divisions NatWest and Ulster Bank.
A week ago, the banking giant paid about £400 million in a settlement with UK and US regulators following its role in foreign exchange rate rigging.
RBS admitted to "unacceptable weaknesses" in its computer systems as around 6.5 million customers - equivalent to 10% of the UK population - suffered disruption lasting for several weeks in some cases.
They were unable to use online banking facilities or obtain accurate account balances from ATMs. Mortgage payments were delayed and customers left without cash in foreign countries.
Among other problems, the banks applied incorrect credit and debit interest to customers' accounts and produced inaccurate bank statements.
The Bank of England's Prudential Regulation Authority, which issued a fine of £14 million, said the failures had the potential to impact on the stability of the financial system by disrupting the clearing system, which is used to settle payments among banks and is fundamental to financial markets.
The issues in June 2012 stemmed from a botched upgrade to the software that processed updates to customers' accounts overnight.
When it noticed problems with the upgrade the bank's central IT function decided to uninstall it without first testing the consequences of that action.
The Financial Conduct Authority, which fined RBS £42 million, highlighted the banking group's failure to put in place adequate systems and controls to identify and manage its exposure to IT risks.
Tracey McDermott, the FCA's director of enforcement and financial crime, said there were "failures at many levels".
She added: "Modern banking depends on effective, reliable and resilient IT systems. The banks' failures meant millions of customers were unable to carry out the banking transactions which keep businesses and people's everyday lives moving."
The meltdown has already resulted in RBS's Ulster Bank receiving a record fine of almost £2.75 million from the Central Bank of Ireland.
RBS chairman Sir Philip Hampton said: "Our IT failure in the summer of 2012 revealed unacceptable weaknesses in our systems and caused significant stress for many of our customers.
"As I did back then, I again want to apologise to all customers in the UK and Ireland that we let down two and a half years ago."
Sir Philip said the bank has since spent hundreds of millions of pounds on increasing the resilience of its IT systems.
RBS said 16 staff forfeited pay and bonuses worth around £6 million as a result of the incident, including the previously disclosed decision by former RBS chief executive Stephen Hester and Ulster Bank boss Jim Brown to waive any bonus that might have been awarded to them in 2012.
RBS and NatWest have over 26 million UK customers, 4,000 ATMs and 2,120 bank branches. Ulster Bank has 450 ATMs and 90 bank branches in Northern Ireland.
The fine by the PRA was the first since it was formed in April 2013.
The regulator said the incident began on June 18 and directly affected at least 6.5 million customers in the UK, 92% of whom were retail customers.
Disruption to the majority of RBS and NatWest systems lasted until June 26 and in the case of Ulster Bank systems until July 10. Disruptions to other systems continued into July.
Bank of England deputy governor Andrew Bailey said: "The severe disruption experienced by RBS, NatWest and Ulster Bank in June and July 2012 revealed a very poor legacy of IT resilience and inadequate management of IT risks.
"It is crucial that RBS, Natwest and Ulster Bank fix the underlying problems that have been identified to avoid threatening the safety and soundness of the banks."
Which? executive director Richard Lloyd said the Treasury should spend the fines on improving financial education for young people, so that the next generation of consumers are better equipped to hold banks to account.
He added: "With record low levels of confidence in banking, regulators must continue to take tougher action to ensure the basics of customer service are improved, access to essential bank services is maintained in every community, and full compensation given to anyone affected by failings."
Business Secretary Vince Cable said: " This is another disastrous fine for RBS after a series of failures. RBS's priorities under Fred Goodwin meant that it neglected its IT systems, which in some cases are now decades out of date.
"The new management is taking action by compensating people and investing in new IT which is right, but in many cases it's too little too late. What matters now is that RBS can continue to overhaul its digital infrastructure to provide the modern services customers and businesses rightly expect."
RBS group chief administrative officer Simon McNamara said that he would prefer not to have to pay the fine but it would not "break the bank". RBS was working to ensure that the problems were not repeated, he said.
Mr McNamara told Channel 4 News: " It's not going to break the bank. But in terms of where we are focused, it is in investing in these capabilities which mean we are not looking at these fines in the future.
"We've invested a significant amount making sure that we are in a much, much better position than we were back in 2012."