By the autumn of 1907, panic gripped the US financial system. The stock market had halved in value and bank runs were spreading from one institution to another, wiping out both the healthy and the weak. Yet from the library of his Madison Avenue home, John Pierpont Morgan used his considerable wealth and reputation to successfully rally New York’s bankers to end the crisis.

A century on and the modern day Morgan resides in windswept Omaha, Nebraska. Warren Buffett, an octogenarian billionaire, son of an isolationist congressman and head of Berkshire Hathaway, a vast conglomerate of businesses, has somehow become the investor of last resort for troubled US institutions.

This week he invested $5bn in Bank of America, lending his stamp of approval to an institution struggling to convince investors that it had set enough capital aside to deal with the toxic legacy of mortgages extended during the days of the housing boom.