Always good to keep some cash outside of the banking system to cover for "glitches" and poor application programming.
RBS is warning its 17 million customers that the backlog caused by a technical glitch could take at least another two days to clear, meaning that the computer failure will have lasted for more than a week.
Customers deluged online forums with complaints yesterday, saying that they were unable to pay bills and were concerned about the impact it could have on their credit ratings.
The crisis has hit customers at RBS and two of its subsidiaries, NatWest and Ulster, and the bank admitted that the chaos caused by a technical glitch is so severe that it does not even know how many accounts are affected.
Yesterday, more than 1,200 NatWest branches were opened on a Sunday for the first time in its history, while a further 1,000 branches will be open until 7pm today in an attempt to ease the problem.
RBS has pledged to compensate affected customers by refunding overdraft charges or penalty fees incurred because of the computer glitch, and help them deal with credit rating agencies. However, it was not clear how long it would take to make refunds.