Since the first problems emerged at NatWest, Royal Bank of Scotland and Ulster Bank, the horror stories have been flooding in. Perhaps one of the most alarming emerged this morning, with one man spending the weekend in jail because of the glitch.
So what happened, and can this man - or anyone else - expect any compensation?
In this particular case, the Daily Telegraph has reported that a defendant in a court case being heard at Canterbury Crown Court in Kent on Friday, was let out of jail for the weekend, on the condition that bail was posted.
By Friday the computer problem was fixed at NatWest, but this particular payment was caught in the backlog, so the unnamed man was left in the cells over the weekend.
HM Courts and Tribunals Service told the newspaper there were actually two cases where a "banking issue" had created problems for defendants. However, for the defendant at the case being heard at Westminster Magistrates' Court in London, the magistrate granted bail anyway.
Many implications have been dramatic and far-reaching. There are unconfirmed reports of a dying British girl in Mexico, whose family were told the life support machine would be switched off because funds had not cleared.
There are other first-hand reports of house transactions not going through, disabled people stranded in their home without food because companies did not receive payment, families left without food, electricity or gas because benefit payments failed to clear, and holidays stopped in their tracks at the 11th hour.
Back to normal
The good news is that most things seem to be back to normal. The bank said this morning: "RBS and NatWest confirm that the update of customer account balances has cleared overnight, with the exception of a few specific sets of transactions. We know this disruption was unacceptable and that many customers will still have questions and concerns. It is possible a small number of customers may experience delays as we return to a completely normal service. We will continue to extend our branch opening hours all week." The banking group is still trying to wade through problems at Ulster Bank.
At the moment, there are people reporting problems with direct debits leaving NatWest current accounts but never arriving.
But what can you do if this crisis has left you out of pocket and experiencing serious hardship?
The bank has already announced that no-one should be left any poorer by the crisis. Susan Allen, Director of Customer Services, RBS Group said in a statement: " We will automatically waive any overdraft fees or charges on current accounts. This will be processed over the next few days."
And for those worried that the last few days will have damaged their credit score she says: "We will work directly with credit agencies to ensure no one has their credit score affected. For all other issues, customers have our commitment that they will not be out of pocket from this issue. We will publish further details on how we will ensure this later in the week."
It has since confirmed that any charges from any other third party due to lack of cleared funds will also be paid by the bank. The Financial Ombudsman's guidance is that people should be left no worse off than if the problem had never happened. Of course, for complex matters like a house sale falling through, this may not be a simple process, as there is bound to be some discussion as to where the fault lay. Likewise, there is no news on the issue of compensation for distress - which presumably would include the stress of spending the weekend in jail.
What you can do
Customers have been encouraged by the Ombudsman to keep records of what has happened to them and their account over the last few days, and stay vigilant for the next few too. We are expecting more details on compensation later this week. However, when any scheme is announced, the more information you have, the better.
You will need a note not just of what happened to your account, but any costs you incurred (with proof where possible) even down to the phone calls you had to make to the bank.
The usual compensation claim rules will apply - where you start with a complaint to the bank, and if you are unhappy with the response the Financial Ombudsman will look at your case.
10 things we hate about our banks
NatWest and RBS chaos sees one man in jail
More than 46,000 of 106,000 the complaints received by the FOS in the second half of last year related to payment protection insurance (PPI). And the organisation is expecting to receive a record 165,000 PPI complaints in 2012/2013.
The huge numbers are due to the PPI mis-selling scandal that should now be a thing of the past, but there is no doubt that the insurance, which can add thousands to the cost of a loan, is highly unpopular!
(Pictured: Martin Lewis after the PPI payout ruling)
Complaints about mortgages jumped by 38% in the last six months of last year, the FOS figures show, compared to an increase of just 5% in investment-related complaints.
Common gripes about mortgages include the exit penalties imposed should you want to sell up or change you mortgage before a fixed or discounted deal comes to an end, and the high arrangement fees charged by many lenders.
While there is nothing in the data released by the FOS about the number of complaints relating to savings accounts, hard-pressed savers have been struggling with low interest rates for several years now.
You can get up to 3.10% with Santander's easy-access eSaver account, but many older accounts are paying 1.00% or less and even this market-leading offer includes a 12-month bonus of 2.60% - meaning that the rate will plummet to just 0.50% after the first year.
Banks are imposing the highest authorised overdraft interest rates since records began, with today's borrowers paying an average of 19.47%, according to the Bank of England.
A typical Briton with an overdraft of £1,000 is therefore forking out around £200 in interest charges alone. Coupled with meagre returns on savings, it's enough to make your blood boil!
While authorised overdrafts may seem expensive, going into the red without permission will cost you even more due to huge penalty fees.
Barclays, for example, charges £8 (up to a maximum of £40 a day) each time that there is not enough money in your account to cover a payment.
If you need to send money abroad, the likelihood is that your bank will impose transfer charges - and offer you a poor rate of exchange. Someone transferring a five-figure sum could easily lose out by £500 or more as a result.
The good news, however, is that you can often get a better deal by using a currency specialist such as Moneycorp.
Automated telephone banking systems, not to mention call centres in far-flung parts of the world, are one of our top gripes - especially as we often encounter them when we are already calling to report a problem.
In the words of one disgruntled customer: "What is it about telephone banking that turns me into Victor Meldrew? Well, maybe it's the fourteen security questions, maybe it's the range of products that they try to push or maybe it's because I'm forced to listen to jazz funk at full volume while my phone bill soars.
"Actually though, I think it's because the people I eventually speak to rarely seem able to solve the issue I'm calling about."
The days of a personal relationship with your bank manager are long gone - for the huge majority of us at least.
When ethical Triodos Bank investigated recently why around 9 million Britons would not recommend their banks to a friend or relative, it found that almost a third felt they were not treated as individuals. Another 40%, meanwhile, were simply disappointed with the customer service they received.
When you're in a rush, the last thing you want to do is wait in a long queue at your local branch.
Researchers at consumer champion Which? recently found that most people get seen within 12 minutes, but you could have a much longer wait if you go in at a busy time. Frustrating stuff!
The Triodos Bank research also indicated that the bonus culture that ensured the bank's high-flying employees received large salaries, even when it was making a loss at the taxpayer's expense, was hugely unpopular with consumers.
About a quarter of those who would not recommend their current banks said this was the main reason why. And with RBS executives sharing a £785 million bonus pool despite the bank, which is 82% publicly owned, making a loss of £2 billion last year, it's not hard to see why.