The post-Berlusconi rally vanished faster than a Maserati. News of the prime minister’s departure had only a fleeting, positive effect on financial markets. By Tuesday morning, Italian bonds were plunging.

The trigger for the sell-off, accompanied by a leap in yields on benchmark 10-year debt to euro-era highs of well above 7 per cent, was a decision by a clearing house to raise collateral demands for trading Italian debt. It is possible that that move, just as it did with Ireland last year, could tip Italy closer to an international bailout Mr Berlusconi has been so desperate to avoid.

The annoucement by LCH.Clearnet, Europe’s biggest clearing house, of an increase margin payments, used to protect counter-parties from the risk of default, on the trading of Italian bonds was followed by 0.73 percentage point jump in Italian yields to 7.48 per cent at their peak on Tuesday. The premium Italy pays over Germany to borrow in the markets rose to 572 basis points, another euro-lifetime high.