Jean-Claude Trichet, European Central Bank president, told banks on Thursday to return to their “traditional role of providing a service to the real economy”, accusing them of having focused too much on “unfettered speculation and financial gambling”.

His strongly worded criticism, at a banking conference in Frankfurt, highlighted European policymakers’ fears that the recovery of the financial market is encouraging bankers worldwide to be­lieve life can return to how it was before the crisis – risking a popular backlash.