Hedge funds have created a "major risk" to global financial stability for which there are no obvious remedies, the European Central Bank warned yesterday in one of the bluntest official statements yet on the rapidly growing sector.

In a clear hint of rising official nervousness about the multi-billion-dollar industry, the ECB ranked an "idiosyncratic collapse of a key hedge fund or a cluster of smaller funds" in the same category as a possible bird flu pandemic as the type of shock that could trigger fresh disruption in financial markets.