Give a trader an inch, and he’ll be desperate to trade a mile.

So we shouldn't be entirely surprised at the way Kweku Adoboli contrived to lose $2bn for UBS through trading on its Delta One desk, presumed to involve exchange-traded funds. And we should be deeply concerned at the failure of UBS to keep a proper eye on him. One UBS executive outside the investment banking space said he was starting to feel like a boxer who has survived several rounds in the ring, only to be floored by a member of the audience.