British banks will have to spend billions overhauling their creaking IT systems over the next few years, Prudential Regulation Authority chief Andrew Bailey told The Independent.
In an interview with the newspaper, Bailey warned lenders of a need to address a patchwork of computer systems.
"This is an industry with complex and quite aged IT - often complex because companies have grown up through acquisition," Bailey said.
"What would be a very bold thing to do is stripping the machine down and rebuilding it instead of bolting bits together in complex fashions so you end up with a very complex architecture," he added.
Bailey also stressed the scale, frequency and severity of cyber-attacks.
"It is a big issue. You cannot mitigate it with capital, and you really cannot ever hope to finally mitigate it because they do not go away," Bailey told The Independent.