Britain's regulatory agencies, it seems, would be glad to be able to wash their hands of responsibility for fighting money laundering. That is understandable: chasing dirty money is a messy business that often takes both companies and regulators into strange territory. Yet it is a key part of the fight against crime and corruption. The Treasury now needs to take responsibility for leadership in that battle.

The difficulty arises because criminals have a variety of ways to make ill-gotten gains look legitimate. Buy a house or a luxury car with cash and then sell it; deposit a suitcase of cash in a foreign bank and then wire the money back to the UK; bet the cash on the horses or at a casino and then cash the winnings; a criminal organisation could even buy a bank.