E-MAIL FROM THE VALLEY: Innovation depends on brilliant but often flaky individuals, who need to be stroked but kept well away from wider responsibility

The Peter principle has always bemused me. Employees will advance to their highest level of competence and then be promoted beyond it, according to Laurence Peter, the author of the concept.

As an observation, it is valid. A colleague's glossy reputation tarnished by a disappointing entry into management - that is a commonplace. All the harder, then, to understand why employers promote staff who are doing fine where they are.

Talent and managerial ability rarely go hand in hand. That is particularly evident in talent-intensive sectors such as investment banking, software and the media. The best news reporters love nothing more than to embarrass authority; the most brilliant developers are attracted to software because it minimises interaction with others; and the biggest revenue generators at investment banks are rapacious individualists.