It could be a horror movie sequel: “excessive risk-taking” by banks is coming back to haunt us. That the warning comes not from Hollywood but from Basel makes it all the more worthy of attention. The Bank for International Settlements showed far more prescience ahead of the crisis than big bankers or the government brain trusts now reforming how they are regulated.

What the BIS warning reveals is that so far, those reform efforts have not succeeded.

In an invitation to a gathering for top central bankers and financiers the BIS worries that “financial firms are returning to the aggressive behaviour [of] the pre-crisis period”. No surprise there: governments are paying them to do so. Financing is essentially free, with central banks charging next to nothing for funds and turning themselves into dumping grounds for dubious collateral. Public treasuries' rescue operations make it inconceivable they would now let a large financial group fail – so risks are “excessive” only for the taxpayers who ultimately bear them.