HSBC was exposed as being lax on security and leaving itself and its customers open to fraud after five-year-old Oliver Pettigrew wandered into a UK branch that had been left unlocked.
According to the Daily Mail, the child simply wandered in through the unlocked door of a branch in North Yorkshire, England, when his parents stopped off at a cash machine.
Although HSBC claimed the emergency services would have been summoned automatically upon anyone attempting to enter the bank vaults, the boy's father managed to walk right up to it without sounding any alarms.
The Pettigrew family could have walked off with computers, hard drives and walkie talkies which were all lying around on desks.
Watchdog Privacy International director Simon Davies told the newspaper: "This is a situation I have never encountered before. It is a failure on multiple levels, on the human level and on the technical level and what it does is expose thousands of customers to a grave risk.
"It could be that the computers are part of a central control system and are password protected and contain no information locally, in which case you don't have the same level of threat. But if they are just password protected then someone could have gained access to the whole central resource of data."
It emerged that the bank had been unlocked for 19 hours before the child's family alerted the police.