Its really not an IT problem, the upside to this for RBS is they can keep a very tight grip of their deposit to loan ratios. They aren't bothered about the customers, its about keeping the bank above the waterline.

http://www.reuters.com/finance/stocks/incomeStatement?stmtTy...

Just look at how very close the Deposit vs. Loan values are, and also consider the timeline of this whole debacle.

RBS downgraded, more loans than deposits, suddenly a "IT problem" that lets them even out the odds a bit, so they can afford to borrow to cover the remainder, and gain much needed liquidity.

http://hat4uk.wordpress.com/2012/06/25/rbsulster-glitch-slog...