Ireland's central bank and new government will confirm on Thursday that the hole in the country's banks is even wider, deeper and darker than seemed to be the case last November, when those bust banks forced the country to go with a begging bowl to the eurozone's rescue funds and the International Monetary Fund (IMF) for 67.5bn euros (£59bn) of rescue loans.

Regulators at the Irish central bank have conducted a review of how much extra capital - as a buffer against future losses - is required by Bank of Ireland, Allied Irish Bank, EBS and Irish Life and Permanent.

Unless something unexpected happens in the next 24 hours, the total amount of additional capital that will need to be injected into these banks will be a bit less than 35bn euros - including 8bn euros that was supposed to be injected into them at the end of February, but was postponed because of Ireland's political turmoil.

Anyway, let's assume that the total amount extra that these banks need is circa 30bn euros. That would take the total quantity of state investment in Ireland banks to a breathtaking 75bn euros (actually a tiny bit more than that).

That is an almost unbelievably large number. When I think about it, I have a small panic attack - because it represents 45% of Ireland's GDP and 55% of its GNP.



(Irish GNP is usually thought to be a better measure of Ireland's useful economic output, because the GDP figure contains a sizeable chunk of profits exported abroad by all those multinationals that settled in Ireland for the exceptionally low tax rate).

Or to put it another way, if Britain's banks had gone bust to the same extent, British taxpayers would have invested something like £700bn in them - or more than 10 times what we actually invested in Royal Bank of Scotland, Lloyds, Northern Rock and Bradford & Bingley.

Nor is that the end of the exposure of the eurozone and the Irish state to these stunningly failed banks.

No financial institution or bank will lend to them. Ireland's banks can't borrow from anyone except the Irish people (who, poor souls, have nowhere much else to put their deposits). But even if they wanted to, Irish households could not possibly put money into the banks fast enough to allow those banks to repay all the institutions - such as German banks - which lent far too much to Ireland's banks in the boom years.

So when these wholesale lenders to Ireland's banks have been demanding their money back (as they have been in a run that has been huge and inexorable), the money has come from the European Central Bank and the Central Bank of Ireland - or, indirectly, from the taxpayers of Ireland and the eurozone.

To prevent Irish banks toppling over one after another, the European Central Bank has lent 117bn euros to them and the Central Bank of Ireland has lent them a further 71bn euros. So that's 188bn euros of loans from the eurozone's taxpayers to Ireland's banks - which makes the 67.5bn euros lent directly by the eurozone and IMF to the Irish government look like peanuts.

And a further 20bn euros of bank bonds - another form of bank debt - is still guaranteed by the Irish state through the Eligible Guarantee Scheme.

So that is 208bn euros of taxpayer loans to Ireland's banks - equivalent to a remarkable 154% of GDP.

To ask the inevitable dumb question, what on earth went so spectacularly wrong?

First, in the frenzied party years before 2008, the banks borrowed too much from other institutions - especially from German banks - and lent far too much to housebuyers and property speculators.

However, to date Ireland's banks have only properly owned up to the losses on the property developments.

On Thursday for the first time they'll be forced to admit that they also face colossal losses on residential mortgages. In February, for example, official Central Bank figures showed that 5.7% of Irish mortgage accounts were more than 90 days in arrears - which means Ireland banks then were owed 8.6bn euros in unpaid interest and principal.

It is pretty extraordinary that it has taken so long for the banks to be forced to recognise their mortgage losses - since house prices have more-or-less halved over the past few years, the economy was in deep recession after the 2008 crash and has subsequently been pretty stagnant, and unemployment has been rising.

Does the phrase "better late than never" apply in this case? Possibly not.

Second, the Irish government probably chose the worst of all strategies for propping up the banks.

By guaranteeing all their liabilities in the autumn of 2008, they turned the bloated liabilities of the swollen banks into public sector debt.

And because the Irish government didn't secure a bottomless borrowing facility from the European Central Bank, it then became impossible to force losses on any of the banks' creditors, even those which lent most recklessly: Ireland did not have the financial resources to pay back all those wholesale lenders that would inevitably have demanded their money back the moment any of them were instructed to swallow a loss.

So some of the guilty parties, namely the wholesale creditors of Ireland's banks - including banks and investors in Germany, France, Spain and the UK - have got away without taking their share of losses. All those losses have fallen on Ireland's citizens, who are not blameless for the mess (they didn't have to borrow too much) but aren't the only ones at fault.

And for the Irish people, there is a second source of possible injustice. The money they've been lent by the IMF and eurozone carries an interest rate of 5.8% on average - which is significantly greater than Ireland's economy and tax revenues can grow right now, and therefore forces Ireland into a potentially never-ending vicious cycle of public spending cuts and low growth.

What's more, the banks may also be trapped in a cycle of forced asset sales and losses, because they are paying out an estimated 2.5bn euros a year for the emergency loans from the ECB and Irish central bank, to finance mortgages and other loans which are falling in value and are not yielding interest.

Perhaps worse still, the 188bn euros of central bank loans could be withdrawn more or less at the ECB's pleasure. So Ireland's banks will continue to feel under relentless pressure to dump assets at punitive fire-sale prices, unless and until the ECB can be prevailed upon to deliver what its officials say it is cooking up, which is a new, longer stable lending facility for banks - such as the Irish ones - that need to reconstructed.

What will be the end of this sorry saga?

By default, it now looks as though almost the entire Irish banking sector will be nationalised.

Allied Irish is already in state hands. Anglo Irish and Irish Nationwide have been crunched together and are being wound up by the state. It will be tough for Bank of Ireland and Irish Life and Permanent to avoid being taken over by taxpayers too.

It will therefore be fascinating to hear what the Irish premier and finance minister lay out as their vision for the future of Ireland's banks. That will be presented at 4.45pm on Thursday, 15 minutes after the Central Bank of Ireland announces the precise, hideous amount of extra capital the banks will be forced to raise.

It will be another momentous day for Ireland and for the Eurozone. But whether it will be a day that sets both on the road to financial recovery, or nudges them nearer catastrophe, cannot yet be assessed.

