When Bank of Ireland employee Shane Travers left his branch at College Green with four laundry bags containing €7.6m it was not the case that his kidnappers simply got lucky and stumbled on a massive cash haul.

In fact the raid was the culmination of months of meticulous planning by a criminal outfit from Dublin's north inner city who knew exactly how much money was held at the bank and how much they were likely to net.

The 'tiger' kidnapping which took place 10 days ago did not happen at the bank in College Green as has been reported; it took place at an adjoining building – the secretive Dublin Processing Centre next door to the retail bank.

Processing centre

Bank of Ireland is unwilling to go into any details about the processing centre or even publicly acknowledge its existence, but the criminals responsible for the biggest tiger raid in history knew that tens of millions of euro is routinely stored at the centre.

There is little doubt that this knowledge came from a current or former bank employee and the extensive garda operation aimed at tracking down the gang is working on this assumption.

The cash centre is where money from all Bank of Ireland branches across Dublin is sent, and it is where cash used to fill ATM machines is prepared.

If a branch is low on cash and needs to be topped up, the money is sent from College Green.

Security at the centre is extremely tight. Staff sources say that employees are weighed each time they come in and out of the building to ensure that they do not steal any money.

Dozens of cameras cover every inch of the counting centre and each employee is monitored by a camera above their individual work stations. A large team of private security guards is on duty 24 hours a day.

Bank officials are very conscious of the possibility that staff working at the processing centre are more prone to being targeted than other employees and it is generally younger, unmarried staff who are employed there to reduce the risk of families falling victim to tiger gangs.

The robbery has made employees across the bank network nervous, and ordinary branch workers are concerned that Bank of Ireland hasn't exactly been quick to point out the distinction between the cash processing centre and an ordinary branch.

This has now led to the assumption that ordinary banks have millions of euro in their safes, which is not the case. Generally, the maximum amount held in bank safes is around ¤250,000, and access is restricted by timelocks.

Because of the success of the College Green raid, it is likely that other criminal gangs will target banks as an easy opportunity to make vast sums of money.

Frustrated

This creates the very real possibility that if an employee from an ordinary branch is kidnapped and only returns with a relatively small amount of money their families could be hurt by criminals frustrated that they have not netted millions.

The proliferation of tiger raids over the past four years has meant that employees are increasingly unwilling to become branch keyholders because of the perceived risk involved.

The Irish Bank Officials Association (IBOA) is keen to point out that the amount of money at the processing centre was the exception rather than the rule. The association will meet with assistant garda commissioner Mick Mc­Carthy tomorrow to discuss security issues.