And, if he still has the relentless desire for success he had as a player, the 50-year-old Glaswegian will prove a hard task-master.

BBC: SPORT | Football | My Club | Motherwell | McGhee out to make his mark

As an individual, Sir David was a hard task-master.

BBC: By BBC News online's Nick Assinder

It's always hard to say how much this kind of personal branding contributes to the success of a business, especially one like fish-farming that's easy to enter but hard to master.

FORBES: Magazine Article