The first response to the saga of Jérôme Kerviel and the £3.7 billion he lost for Société Générale might be an element of Anglo-Saxon smugness. This would be entirely misplaced. A nation that offered the world Nick Leeson and the demise of Barings Bank in the 1990s and that managed to manufacture the Northern Rock debacle more recently is in no place to lecture others. There is not much merit in piously insisting that “it could never happen here” when, in many ways, it has happened in Britain in the not too distant past, and could happen, institutionally if not individually, at some moment in the future.

Humility having been established, however, if the alleged “facts” of this matter are really as they have been presented then truth is not only stranger than fiction but makes the world of the imagination appear tediously commonplace by comparison. If the official narrative is to be believed then Mr Kerviel was some sort of Clark Kent turned Superflop, a man charged with the responsibility of overseeing a comparatively tiny sum of money as a virtual office junior who by means unspecified managed to make himself responsible for effectively “betting” vast sums of money, consistently ineffectively, with no one in a position of seniority noticing because he alone understood the practices of the “back office” (internal administration and risk control) and the “front office”, the more glamorous realm that is trading. As a one-man alleged “inside job” this is quite amazing.

So amazing, that it has to prompt profound questions that the Société Générale management does not seem especially keen on answering. It beggars belief that no one took any interest in Mr Kerviel's increasingly reckless trading. There has to be the suspicion, at a minimum, that there were people higher up in the bank who, even if they were not aware of Mr Kerviel's wagers at the beginning, must have then collaborated in a desperate if unsuccessful attempt to limit the financial damage after. If there were not, then that should not be cause for relief but for a different series of searching questions. It would imply managerial negligence on an absolutely breathtaking scale. This is a complicated affair in many respects. Yet it boils down to the familiar search for “who knew what and when?” and the sooner this can be answered the better.

For there is a crucial difference between the Leeson fiasco and the implosion of Barings and this incident. The mistakes that one rogue trader made in Singapore might have destroyed a venerated British institution with an historic name but its impact on the global economy at large was modest. There was no stock market crash that was triggered by or augmented by that moment. There is, by contrast, real reason to wonder if a significant part of what occurred in the world economic system earlier this week was not solely the consequence of Asian markets taking fright at the prospect of a US recession this year but the effect of SocGen seeking, secretly, to cut losses. Did this bank tell the regulators in France of its immense difficulties and if so when? Did those French regulators, in turn, refer this up to European authories as they should have done? Did these bodies then use the hotline to the Federal Reserve and other interested parties? If, as it has to be assumed, Mr Kerviel was not part of the Federal Reserve's information pack when it held its emergency meeting on Monday evening, did it unwittingly cut rates because of him?

In practice, it might have acted even if it was completely aware of what was occurring. Even so, what this strange incident illustrates is the degree of connectivity that exists across the world's financial markets that can be transmitted to the respective “real” economies. Northern Rock was not directly involved in lending to high-risk Americans who aspired to buy their own homes but the consequence of the subsequent credit crunch was that its business model was torpedoed. The American monetary authorities probably spend little time discussing internal procedures at Société Générale but might have found themselves spooked by what happened in that bank regardless. This is an epic whodunnit that must be unravelled, but that may not be resolved if it is left to the bank itself to investigate.