In the spring of 1984, an agitated Jack Welch travelled to an investor conference in Florida determined to allay Wall Street analysts' fears over General Electric's growth prospects.

But instead of launching into one of the number-heavy perorations so beloved of GE's executives, Mr Welch walked to the overhead projector and slapped on a slide. Black clouds emblazoned with GE's perceived weaknesses appeared on the screen, providing Mr Welch, who had been named chief executive three years prior, with a typically forthright opening line.