Over the centuries, literally hundreds of millions of words have been written trying to define what constitutes success for leaders.

In theory, it’s easy. You can pick someone from history, such as Napoleon and talk about his great victories on the battlefield. Was he a successful leader?

Alexander the Great conquered much of the then known world – was he successful?

More recently, across the globe politicians have become household names because of their radical social programmes. So have certain business people who have accumulated unimaginable personal fortunes. Are those examples of that most ephemeral of things, ‘success’?