Banks are believed to face several thousand electronic attacks everyday and have spent hundreds of millions of pounds improving their systems to make them more secure.
Andrew Haldane, director of financial stability at the Bank of England, warned in June that cyber attacks were now a greater risk to the banking system than the eurozone debt crisis.
Mr Haldane told MPs that he had recently met five of Britain’s biggest banks and that four had said that cyber attacks were had become the greatest threat to their businesses. He added that the fifth bank had recently upgraded cyber attacks as one of its key risks.
“You can see why the financial sector would be a particularly good target for someone wanting to wreak havoc through the cyber route,” said Mr Haldane.
He added: “Understanding and management of this risk was still at a somewhat early stage.”
The Bank of England’s Financial Policy Committee has made the cyber threat to banks one of its main focuses and has recommended that government departments and the industry work together more closely to monitor the problem.
The results of the regulator’s cyber attack benchmark of the banks is unlikely to be published given the security risk of revealing which lenders might be particularly vulnerable.
Every major bank provides online banking services to their customers, however with this has come the increased risk of criminals and terrorists infiltrating individual accounts or even bringing down entire systems.
The US authorities revealed earlier this year that one crime gang had stolen $ 45m from banks in the Middle East by hacking credit card processing systems.