Stamina, intelligence, ego: which personality traits make the best leaders?

Some say a second-class mind makes for a first-class leader, others that madness is an essential feature of the role. From Trump and Obama, to Blair and Boris Johnson, which personalities are born to rule?

There is a story that often gets told about modern presidents and prime ministers, and sometimes gets told by them as well. The politician spends half a lifetime working tirelessly towards the top job, with the goal of making a real difference once he or she gets there. They issue their instructions. Dutiful officials nod along encouragingly. But nothing really changes. Once the door to the Oval Office or No 10 closes behind them, and they settle their feet under the desk, the new president or prime minister finds out that it's just another room and just another desk. It feels as if true power is still somewhere out of reach.

In politics you should never assume that there is a pot of gold at the end of the rainbow. It's better to know how little is waiting for you, like a weird inversion of the parable of The Wizard of Oz. In place of the Yellow Brick Road is the greasy pole, which has to be ascended to reach the Emerald City. Yet the successful climber finds that his or her fate is not to encounter a shrunken wizard at the end of it. Instead it is to become that person: the impostor behind the curtain.