And a report prepared by France's finance ministry criticised SocGen's procedures for monitoring its trades, adding to the pressure on Daniel Bouton, the bank's chairman, to step down.

ECONOMIST: Business this week

Daniel Bouton, SocGen's boss, has argued that Mr Kerviel could easily conceal the vast positions he took because he had previously worked in the back office, so was familiar with the system of controls.

ECONOMIST: Soci��t�� G��n��rale

Yet Daniel Bouton, SocGen's boss, thinks that the two banks have too many overlapping branches to make such returns possible: in regulated France, you cannot simply close branches and sack people, which is, in part, how banks in America and Britain have increased returns.

ECONOMIST: French banking