Succession planning for the role of chief executive is never easy. When Jack Welch led General Electric he kept his immediate subordinates guessing right up to the day of his departure, knowing that headhunters were forever circling his top team, looking for an opportunity to move for the unsuccessful candidates.

Anointing a successor too early would have deprived the company prematurely of some of its most formidable executives. At the same time it would have removed the stimulus of competition as a motivating force.