The British government faces an excruciating choice. It cannot let Royal Bank of Scotland and its fellow mega-banks go to the wall. Yet it risks being swamped by the massive foreign debts of these lenders if it takes on their dollar, euro and yen exposure by opting for full nationalisation.
Britain has foreign reserves of under $61bn dollars (£43.7bn), less than Malaysia or Thailand. The foreign liabilities of the UK banks are $4.4 trillion – or twice annual GDP – according to the Bank of England. The mismatch is perilous.
It is why sterling has crashed 10 cents from $1.49 to $1.39 against the dollar in two days. The markets have given their verdict on Gordon Brown's latest effort to "save the world".
Credit default swaps (CDS) measuring risk on British debt have reached an all-time high of 125 basis points, just below Portugal. The yield spread on 10-year Gilts over German Bunds has doubled to 53 basis points since last week.
Standard & Poor's has quashed rumours that it will soon strip Britain of its AAA credit rating – an indignity averted even after the International Monetary Fund bail-out in 1976. But there was a sting yesterday as it responded to the Treasury plan for the banks. "Market confidence in the sector has eroded to such a degree that it is not clear whether these measures by themselves will bring about a material improvement," the IMF said. "As a result, full nationalisation of some banks remains a possibility in our view."
Spain was relegated from AAA to AA+ on Monday, and Spain's public debt is a much lower share of GDP.
"If Spain can get downgraded, then the risks for the UK are self-evident," said Graham Turner, of GFC Economics. "The increase in the UK gross public debt burden – 11.8 percentage points in just one year – is troubling. The market rightly fears the long-term fiscal costs of a collapsing banking system. Rising Gilt yields are the main impact of the botched move from the UK Treasury."
Mr Turner said the British Government had taken far too long to resort to quantitative easing – printing money – and had wasted months with fiscal frippery as debt deflation throttled the banks.
The parallels with Iceland are disturbing. The country was ruined by the antics of its three big banks. They built up foreign liabilities equal to 900pc of GDP. Operating as hedge funds, they borrowed in dollars, euros and pounds to speculate. However, the state lacked the foreign reserves to match this leverage.
But Iceland at least had the luxury of letting banks default – shifting losses on to the rest of the world. It refused to honour foreign debts.
"They drew a line," said Jerry Rawclifffe, who tracks Iceland for Fitch Ratings. "They created new banks, parking the old losses in resolution committees. It is not easy for other governments to walk away. They have a duty of care."
Indeed, if Britain walked away from UK banks' $4.4 trillion of foreign liabilities – worth eight times Lehman Brothers – it would destroy the credibility of the City and take the whole world into deeper depression.
"The UK cannot go down that route because it would set off an asset price death spiral," said Marc Ostwald, a bond expert at Monument Securities. "The Western banking system is already on life support. That would turn it off altogether."
So whatever the temptations, and whatever the feelings of righteousness over the follies of the RBS leadership in its debt-driven campaign of Napoleonic expansion, the Treasury is wedded to the banks and all their sins. Chancellor Alistair Darling cannot copy Iceland.
S&P's lead UK analyst, Trevor Cullinan, said the Government faces a "severe test" and will be judged by its actions, but he doubts whether matters will reach such a dangerous pass.
"The challenges to UK banks are significant amid a correction in property prices and a contraction of GDP. Nevertheless, the situation is very different from Iceland. The UK benefits from sterling, which is a major global funding currency. UK access to external funding is far more secure. In a worst-case scenario we estimate the cost of recapitalising the UK banking system to be in the region of £83bn (5.7pc of GDP)," he said.
The Government can take out derivatives contracts on currency markets to hedge the foreign debt risk. Perhaps it already has. The banks have $4.4 trillion foreign assets to offset their liabilities, of course. But what is their real value in this climate?
Britain is not alone in its current distress, although the fall in sterling speaks for itself. The sovereign debt of Russia, Ukraine, Greece, Italy, Belgium, Austria, The Netherlands, Ireland, Australia, New Zealand and Korea is all being tested by the markets. The core of countries deemed safe is shrinking by the day to a half dozen. Sadly, Britain is no longer one of them.
