A few weeks ago, after I had written about the culture that enables the DIRT and Ansbacher frauds, I had a letter from a former bank official raising an issue that I would normally prefer to avoid. The man, a Catholic, wanted to draw my attention to what he saw as the role of religious attitudes.
He wrote as follows: "It is a sad fact that as the religious composition of Irish bank officials tilted from being Protestant to Catholic, the sense of `ethical banking' has declined in inverse proportions.
"I joined the Bank of Ireland in 1970 at College Green (as a Catholic from Galway) when the officials were 75 per cent Protestant. There was an almost religious sense of duty to managing Ireland's finances and at that time the Bank of Ireland, not the Central Bank, issued and managed government loans.
"Samuel Beckett had invested his family inheritance in Irish bonds at four per cent per annum and many others followed suit. These were then ridiculous returns on capital, but you get the picture - helping Ireland was more important than financial returns.
"Later, when I went to Sligo to learn about branch banking, there was the same earnestness, the same sense that it was a privilege and a solemn duty to look after the customer's finances. There was great interest in being honest and truthful.
"But the merger of the bank with the National Bank and the Hibernian to form the Bank of Ireland Group changed the ethical basis almost at once. From then on, the emphasis was on growth, on gaining new business at all costs and on cutting corners so as to prevent AIB from advancing. In fact, what happened very quickly was that Irish banking went `gombeen' almost overnight. Professional attitudes were considered old hat. (There was) a nod and wink to tax evasion and government returns.
"It is, I think, one of the great paradoxes of the last 20 years that Ireland's banks were more ethically managed when staffed by Protestants, who were then considered suspect on national ideals, than by a Catholic majority who seem to have very few scruples and even fewer ideas of what it really means to be Irish."
I would normally be most comfortable attacking this kind of stereotype, particularly when it involves the kind of sectarian typecasting that has been so destructive in Ireland. Most generalisations about categories of people reflect little more than ignorance and prejudice. The image of the honest, dutiful, upright Prod and the wily, shifty, untrustworthy Tague is so much a part of the deadly sectarian mindset in Northern Ireland that the proper instinct is to stay a million miles from anything that seems to reinforce it.
And yet, before dismissing my correspondent's experience as either exaggerated or untypical, two aspects of the response to the current revelations about Irish banking have to be acknowledged.
One is that the attitude of the bank whose culture is still most obviously Protestant, Ulster Bank, was markedly different from that of the other institutions. The other is that Protestant clergy have been much more forthright than their Catholic counterparts in their comments.
One of the stranger experiences for those watching the Public Accounts Committee hearings on the evasion of DIRT was the general demeanour of the Ulster Bank witnesses. Their bank was not angelic but neither was it a serious offender.
Much of its paperwork in relation to DIRT in the early 1990s was sloppy and the bank probably failed to pay about £1 million in tax between 1986 and 1998. Ulster Bank did eventually get its act together, though rather more slowly than it should have done. This is hardly a cause for pride but neither is it, in the overall context of the scandal, especially shameful. Yet the weird thing about Sir George Quigley, the bank's chairman and a former head of the department of finance at Stormont, and about his colleagues was that they did seem genuinely ashamed.
They didn't try to claim that they had secret amnesties whose existence could not be committed to paper. They didn't try to make excuses. They didn't try to throw dirt at their accusers. They didn't even complain about the vagueness of the laws or the lack of real enforcement.
They simply said three things: we did wrong, we are ashamed of ourselves and we accept without question that we now have to pay whatever tax we owe.
This might not seem especially remarkable in itself. But in the surrounding murk, the Ulster Bank shone for its contrition and lack of arrogance.
A cynic might say that coming out with your hands up and being polite and humble is good business for a company that depends on public trust. But if it's such good business, how come the rest of the business elite appearing before the committee didn't think of it? Hardly any of them managed to look sorry. Only a small few could muster even the appearance of shame.
And it's not hard to understand why. They couldn't act ashamed because they felt no guilt. They didn't bother with the act of contrition because they genuinely don't think they have committed any sins. If they came across as smug, self-righteous people who could barely contain their anger at having to answer questions from these uppity politicians, that's because they are.
And it's not completely outlandish to suggest that this may have something to do with the broader ethical culture of the Irish Catholic middle class.
It's not, of course, that Catholicism itself is soft on crime or that it lacks a profound moral sensibility. It's not, in a real sense, to do with religion at all. But it does mean that a specifically Irish Catholic sense of what a good businessman was supposed to be failed miserably when it was put to the test.
However hard the Jesuits and other orders may have tried to inculcate in their pupils Cardinal Newman's ideal of the Catholic gentleman, they clearly didn't get very far. The teaching orders who justified their concentration on educating the children of the rich by claiming that they were turning out an ethical elite have a lot of rethinking to do.
Nor has the leadership of the Catholic Church managed to articulate in plain terms the immorality of what large parts of the business and political class has been up to.
Senior members of the Church of Ireland, by contrast, have spoken out in terms that could hardly be less uncertain. The Archbishop of Dublin, Dr Walton Empey, spoke of paying one's taxes as not merely a legal obligation but as a religious imperative, "our plain Christian duty". He spoke of the need for the full rigour of the law to be directed against those who are found guilty of tax evasion.
This week, too, Archdeacon Gordon Linney spoke of "a Government which failed to confront its friends in business". If the Catholic hierarchy could speak as directly as this about the gross immorality at the heart of the Irish elite we might be able, with more confidence, to banish the last vestiges of a dangerous sectarian stereotype.