There comes a time in the life of every leader when the circus tent is subsiding gently down its pole and there’s an ominous silence coming from the animal cages round the back, that one begins to gaze out past the angrily drunk clowns vomiting behind the hay-bales and think about one’s legacy.

For some, this means it’s time to write a book, or at least dictate it to a someone who has once read one...