One of the many perplexing aspects of the scandals that have torn apart some of Britain's biggest banks is why so few of the chairmen, top executives and non-executive directors didn't see the problems coming. Or, if they did, why they were either unable or unwilling to stop them, or at least flash up some warning signals.
Did Fred "the Shred" Goodwin really run RBS so much like the Kremlin that no one on his board dared challenge his strategy? Was Bob Diamond so venerated as Superman for his bold efforts to build Britain's only serious investment bank to the point that the board – and senior executives – turned a blind eye to his faults?
Self-interest is clearly one of the answers. By going along with Goodwin and Diamond, their colleagues were party to the eye-watering incentives and bonuses that flowed from the aggressive strategies of their bosses.
It may seem a little late to be asking how HSBC and Lloyds allowed such disasters as the mis-selling of payment protection insurance, interest-rate swaps or Libor manipulation nearly four years on from the crash. Even most bankers, as well as the public, will shrug their shoulders and say, well; it's the greed, stupid. But it's not a good enough analysis.
Unless we dig a little deeper and discover precisely how some of the our most prestigious institutions were hijacked by such immensely powerful characters, similar scandals will continue. Edmund Burke's warning that those who don't know their history are destined to repeat it is all the more pertinent today. His words came to mind when watching Antony Jenkins, the Barclays chief executive, tell MPs last week that he had disagreed with Diamond, his former boss, over strategy and that they had had many "debates" over business practices. It sounded lame, and begged the question as to whether Jenkins had passed on his fears.
If he did, it would be interesting to find out to whom. As we now know, the Financial Services Authority and the Bank of England also had serious reservations about Diamond's appointment as chief executive because of the aggressive way in which Barclays Capital was being run.
So you have to ask whether the corporate structure at Barclays, and maybe many of the UK's top companies, are fit for purpose if senior directors and regulators, aren't getting their messages through to the board or investors. The same questions should be asked of RBS's top executives and non-executives (NEDs) – heavyweights such as Sir Tom McKillop, Peter Sutherland and Steve Robson, a former permanent secretary.
None of them have been held accountable; yet John Hourican, the head of RBS's investment bank, has been sacrificed over the Libor scandal even though he wasn't there at the time most of the manipulation was being carried out. Something looks horribly wrong.
It's time for more research into the governance of British boards, particularly the relationship between the executive and the part-time non-executives, how risk is evaluated and, in the jargon, how to avoid "groupthink". It may well be that our model is broken; more suited to the 19th century than the 21st, where the risks for big multinationals have become so complex that NEDs are no longer capable of being heard.
Risk is something John Hurrell, the chief executive of Airmic, understands. Mr Hurrell represents risk managers at about 500 of the UK's biggest companies. He commissioned research last year from the Cass Business School to investigate the causes of some of the world's most awful corporate catastrophes such as those at AIG, Northern Rock, Shell, BP's Deepwater Horizon and Railtrack. What he, and his members, wanted to know is if there were any common underlying causes.
Even Mr Hurrell was shocked at the report's findings, which showed there were seven causes highlighted in 17 of the 18 case studies, and 22 of the 23 companies involved. All these factors were directly related to the failure of company boards to access and act upon information that was already in their sphere of knowledge.
In most cases, the Roads to Ruin study concluded that if the information had got through to the top executives, those catastrophes could have been either avoided or mitigated. That's more than coincidence. He calls them risk "glass ceilings", and what the research showed most vividly was the inability of internal audit teams to report back on the risks which had originated from the highest levels of their organisation's hierarchy. It also revealed many other limitations on the competencies of most boards, and the inability of the NEDs, to monitor and, if necessary, control the executives.
Being a non-executive is already a hellish role at the best of times; part Mother Teresa, part policeman, part judge. It may be that the plural life of most NEDs, who often spend only a couple of days a month at any one company, is outdated.
Instead, perhaps, boards should be looking to recruit "independent" directors who have only two or three other outside interest. Coupled with more training, this might make them tougher and able to put the company interest, in its widest sense, above self-interest.
There are all sorts of other things that need looking at: who heads remuneration committees, whether there need to be better mechanisms for executives below board level to flag up concerns or easier whistleblowing.
What is sure is that how companies are governed needs some clever thinking and a fresh eye. It's a pity that Justin Welby has just become Archbishop of Canterbury, as he would be perfectly suited to head such a brain-storming. Maybe he knows someone who can help out.