WPP needs a big name to follow Sir Martin Sorrell

The advertising giant can’t go on for ever as a one-man bandThe advertising giant WPP Group has a board consisting of 14 directors. Chief executive Sir Martin Sorrell is one. Name any of the others.As far as financial teasers go, that one has the potential to stump more folk than just Diane Abbott. Even among those who take time to actually read the City pages, it is a struggle to recall anybody other than the group’s diminutive founder when pressed for a line-up of WPP management. C