The two sides of the ECB's balance sheet must match. The loans to the PIIGS banks are the ECB's assets; they have their counterpart liabilities in cash balances maintained by banks from Germany, the Netherlands, Luxemburg and Finland. The ECB's capital is tiny relative to its overall balance sheet, a mere €10 billion relative to about €3,000 billion. What happens if the PIIGS' banks do not repay to the ECB the €980 billion which, according to the latest data, they owe to it? Clearly, somebody must     lose. Who is that? The answer is the banks from Germany, the Netherlands, Luxemburg and Finland, which at present have positive balances at the ECB of more than €1,050 billion. 

The Maastricht Treaty of 1992-one of the high points in the tragi-comedy of the euro — included a specific no-bailout clause (article 125 of the Treaty on the Functioning of the EU). This prevented, or seemed to prevent, one nation being obliged to honour the debts of another. But, despite all the clever stage management, the impresarios blundered. They overlooked that, in the normal course of banking operations, the ECB could incur debts that were in reality those of eurozone member nations. 

The first big rescue loan in the eurozone, to Greece in May 2010, was largely between governments and used a let-out clause in the TFEU (article 122 on emergency support because of "natural disasters"). But since then the rescue operation has been conducted across the balance sheet of the ECB. It is widely and correctly understood as a "backdoor bailout". 

Spain, Italy and the others may receive more credit from the ECB in coming months, with the support of a German government anxious somehow to keep the euro intact. But the larger the ECB's balance sheet, the greater is Germany's possible future loss. Der Spiegel has invented a beautiful word for the looming disaster: die Geldbombe — "the money bomb". What a super title for a future Whitehall farce.