Last month RBS' chief executive Stephen Hester said that the banking group may have avoided the major IT glitch if it had focused more on keeping its existing systems up-to-date, .

"RBS has seen a big mushrooming in spending on technology. With hindsight maybe a bit more of that increase in spend should have been in the core, taken-for-granted systems that work every day," said Hester.

"Some of our focus was on the new things people want."