If Jamie Dimon plays poker, let's hope he is better at bluffing when he is playing for poker chips than he was when he was playing for the future of Bear Stearns.

Just one week ago, Dimon was hailed as the saviour of Wall Street by everyone except staff and shareholders at Bear Stearns, after he led JP Morgan Chase to an audacious $2 a share bid for the failed investment bank. The deal, backed by a $30bn guarantee from the Federal Reserve, virtually wiped out shareholders in the bank, but averted - if only temporarily - meltdown in the financial markets.