Four Lloyds Bank workers who helped fraudsters to steal millions of pounds from rich customers using a string of impersonators are facing jail.
The insiders scoured the computer system for rarely-accessed accounts holding large sums of money before passing the details to the criminal gang.
They also ordered new bank cards so that imposters could pose as the customers and set up transfers of hundreds of thousands of pounds at a time.
The money was next laundered through a series of bogus companies before being moved offshore to prevent it being recovered, it is claimed.
One victim lost more than £750,000 after a unknown man used a fake driving licence in his name to set up two transfers over three days.
Another customer with £3m in the bank only escaped becoming a victim when another member of staff became suspicious and rang him up to check.
Bank workers Courtney Ayinbode, 29, Tajinder Galsinh, 35, Molly Jones, 24, and Benjamin Omoregie were all involved in the 'high-level and sophisticated' scam.
Kushveer Raulia, 25, operated a network of bogus companies to launder the proceeds while Parvez Hussain, 50, laundered some of the cash.
Prosecutor Paul Cavin told the Old Bailey: "They were all involved in an agreement to defraud Lloyds TSB of millions of pounds.
"Accounts belonging to people with large balances - in some cases several millions of pounds - were targeted.
"To identify those rich accounts, an insider, an employee of the bank was recruited to help the gang.
"The insider would then assist in breaching the security protocols in order to steal the money.
"The money would be transferred to accomplices who would swiftly transfer the money through a number of bogus businesses before eventually the money would disappear offshore.
"Once it is offshore it can come back onshore and nobody can trace it."
The first victim lost £750,975 in the space of three days after his account was accessed by both Ayinbode and Omoregie at the Balham and Streatham branches of Lloyds TSB in July 2013.
A few days later the customer's address was changed and a new card was issued to the new address, it is claimed.
Then on 5 August a man claiming to be the customer went into the Kings Cross branch to ask to set up a transfer.
Staff accepted the imposter's bogus driving licence as genuine and authorised the transfer, even though the customer's local branch was in Clapham, south London.
The money was laundered through a bogus company operated by Raulia, it is claimed.
Mr Cavin said: 'Raulia provided a ready made money laundering structure, limited companies with bank accounts both here and overseas.
'What these accounts allow you to do is to transfer money to a number of other accounts that equally do not seem to have any legitimate purpose.'
Raulia then allegedly withdrew 'significant quantities of cash' and used £860 of it to pay off his credit card, it is claimed.