Jean-Pierre Mustier, head of corporate and investment banking at Société Générale, is a big fan of Sun Tzu’s The Art of War, which recommends getting to know your enemy and ensuring your army is better trained than that of your adversary.

When he stands before the bank’s board on Wednesday to explain how one of his traders built up huge unauthorised positions that ended up costing SocGen €4.9bn ($7.2bn), Mr Mustier will know his enemy well, but may regret not training his troops better.