'If you look at coaches and mentors, they are generally people who have not actually run big businesses themselves, so how can they tell you how to do it?' - asks Sir Martin Sorrell.
That quote is taken from 'The Secrets Of CEOS' by Steven Tappin and Andrew Cave, published in 2008.
And, it is a very good question.
Here is my reply: video 9 minutes and 14 seconds.