Societe Generale sacrificed Jerome Kerviel

The Jerome Kerviel case demonstrates how we should watch the quiet ones in the office closely but ensure that the buck still stops at the top.

His peers called him "Monsieur Personne": Mr Nobody. But this modest son of a Britanny metalworker, his mother a hairdresser, has now managed to make quite a name for himself even outside financial circles.

Supposedly working alone, often at night, without any senior management having the slightest inkling of what he was doing, Jerome Kerviel was quietly betting €50 billion, almost all the capital of Societe Generale, one of France's oldest and grandest banks, on a series of complex bets.

If they came off, he would have netted a fortune, both for himself and the bank. Unfortunately, events conspired against him, his activities were discovered, and in the spring of 2008 his positions were unwound, leaving the bank with a €4.9 billion loss.

The bank has managed to persuade a French court that it was all Monsieur Kerviel's fault, and that as well as spending three years in jail, he must also repay the money. On his current salary with a new employer, he would have to work for 170,000 years to do so.

Clearly Kerviel's actions were unwise and unauthorised. But shouldn't the bank itself accept a portion of the blame? A state banking commission found serious failings in the bank's supervision of its traders. Yet again, though, senior management have escaped censure.

"I feel they wanted me to pay for everybody and they killed soldier Kerviel to save the general," he said after the verdict was announced. We should watch the quiet ones in the office closely, but in future ensure that the buck stops at the top.