Scandals emanating from the boom years should have lost their power to shock. But evidence unearthed by US and UK regulators showing how traders and managers at Barclays connived to manipulate a key market interest rate used to benchmark trillions of dollars of loans and derivative contracts is enough to stir even the most jaded cynic.

The UK bank, which has agreed to pay $453m in fines, is the first to settle with regulators in a wide-ranging investigation involving most of the leading global investment banks into rigging of the London interbank offered rate, or Libor. Barclays can live with the fine, but damage to the bank's reputation and that of its top management, none of whom has resigned, could be lasting.