Twelve men have been arrested over an alleged multi-million pound cyber plot to take over Santander bank's computers.
Thousands of workers are facing mounting uncertainty over their jobs after the collapse of a proposed sale of RBS branches to Santander.
The chief executive of the RBS said it was "disappointing" that a proposed sale of 316 branches to Santander had collapsed.
Police have released an image of the type of device used by a cyber gang in a foiled attempt to steal millions of pounds from a Santander bank branch in south-east London.
The Metropolitan Police, who arrested 12 men in connection with the attempt, said a plotter had posed as an engineer to fit a keyboard video mouse (KVM) device to a computer at the bank to transmit its desktop contents.
Using the gadget, the gang remotely took control of all the computers at the branch in Surrey Quays shopping centre, but the Spanish bank said they were unable to steal any money.
The bank branch pulled its shutters down and queues of worried customers used the cash points outside to check whether all funds were still in their accounts. No money had been taken.
Santander has said no money was ever at risk and no member of staff was involved in the foiled plot to steal millions from the bank's branch in Surrey Quays, south-east London.
Like all high street banks, Santander works very closely with the police and other authorities to help prevent fraud.
Through this co-operation, Santander was aware of the possibility of the attack connected to the arrests. The attempt to fit the device to the computer in the Surrey Quays Branch was undertaken by a bogus maintenance engineer pretending to be from a third party.
– Santander spokesman
It failed and no money was ever at risk. No member of Santander staff was involved in this attempted fraud. We are pleased that we have been able, through the robustness of our systems, to prevent the fraud and help the police gather the evidence they needed to make the arrests.
The Metropolitan Police's Central e-Crime Unit said the foiled plot to steal millions from a Santander bank computer at a branch in London was on a scale they had never seen before.
– Detective Inspector Mark Raymond
This was a sophisticated plot that could have led to the loss of a very large amount of money from the bank, and is the most significant case of this kind that we have come across.
I would like to thank our partners from the industry who have provided valuable assistance throughout this investigation.
The PCeU is committed to tackling cyber-crime and the damage it can cause to individuals, organisations and the wider economy.
The attempted multi-million pound theft at Santander involved fitting a keyboard video mouse (KVM) device to a computer within the bank's Surrey Quays branch, the Metropolitan Police has said.
This would allow the suspects to view the desktop contents of the bank computer and take control of it from a remote location.
The Met said: "Yesterday's time-critical, dynamic response was achieved by working in partnership with the banking sector, thwarting a very significant and audacious cyber-enabled offence."
The 12 men arrested are being held at a London police station following searches at a number of addresses across the capital.
Twelve men have been arrested over an alleged plot to take over Santander Bank's computer to steal millions of pounds from the bank.
The group are accused of fitting a device to a computer within the bank's Surrey Quays branch in south-east London and attempting to remotely control the bank's main computer.
Eleven men, aged between 23 and 50, were arrested in Hounslow, while a 34-year-old man was held at Vauxhall Bridge Road.
The arrests yesterday were the result of a long-term investigation by the Metropolitan Police's Central e-Crime Unit, which described the alleged plot as "audacious".
Virgin Money is being heavily linked to a bid for the network of Royal Bank of Scotland branches that failed to be bought by Santander.
The Sir Richard Branson-backed bank, which took control of nationalised Northern Rock in January, was said to have been "very keen" on the business when it was up for sale in 2010 and is now considering the opportunity to rebid.
Buying the RBS division would more than quadruple Virgin's branch network and add a small and medium-sized business bank to its offering.
Virgin Money, the UK financial services firm that last year bought Northern Rock, would be "very interested" in taking a look at a portfolio of 316 branches that Royal Bank of Scotland has put back up for sale, a source said.
The source said Virgin Money is keen to grow further after the Northern Rock deal and would take a look at the business on offer, but whether it would pursue a deal would depend on issues like integration prospects and price.
Santander on Friday pulled out of the £1.65 billion ($2.65 billion) deal to buy the RBS branches, which come with 1.8 million customers, more than two years after it was struck, blaming delays in its completion.
Thousands of workers are facing mounting uncertainty over their jobs after the collapse of a proposed sale of Royal Bank of Scotland branches to Spanish banking giant Santander, it warned.
Unite called on the government to press the European Commission to lift its requirement for RBS to sell 316 branches and other assets.
Gail Cartmail, Unite's assistant general secretary, said:
This latest development is causing yet more uncertainty and represents another day of chaos for loyal RBS staff.
"The real danger is that the European Commission's requirement to sell branches and assets by the end of 2013 will result in a fire sale and an attempt by any buyer to strip out costs and drive down terms and conditions of hard working staff.
"At the very least the commission should give RBS more time to ensure that a buyer is found which is good for the taxpayer and the economy, right for competition and above all right for staff, their terms and conditions, job security and future."