AFTER the funeral, I was talking to a former parishioner. She has married into politics - her husband is close to the heart of New Labour. He commuted daily to Downing Street when they held power. But tonight she was breaking ranks and going to hear Boris Johnson. "I shouldn't really," she said, excitedly, "but, well, you've got to like him." Is this what they call charisma?

A recent documentary suggested that Hitler had great personal charisma. It is not immediately obvious across the years; you had to be there, apparently. On the face of it, this brutalised child and failed artist rose to power solely through his ability to speak. He did not like policy discussions, and was unable either to listen or relate, but he could hold an audience. He was not an interesting speaker, but he was effective because his hate made a confusing world more simple and reassuring.

Charisma does not exist on its own, but in relationship to an audience that is being told what it wants to hear; and the essence of Hitler's charisma was his hatred for the "unworthy life forms" that Germany was supporting. All else, including the power of his oratory, sprang from the force of this destructive psychology. And Germany in the 1930s loved him.

Meanwhile, in a very different climate, David Cameron is apparently looking over his shoulder nervously at Johnson. Why? Because Boris, as we call him, is the closest we get in England to a "charisma" politician.

This is privileged status, granting the individual the goodwill of everyone, and possibly their vote, even if they do not like his or her policies. Although many say he has done a great deal for himself as Mayor of London, Londoners may be struggling to say what he has done for them. Both the Olympics and the "Boris bikes" emerged on the watch of the city's previous mayor, Ken Livingstone.

There is a hint of attention-seeking in the air, a craving for visibility and applause, but who cares about these things when he is such an entertaining speaker? "You've got to like him," as my friend said, a commitment to the man which most politicians can only dream about.

Charisma used to be a holy word, denoting a divinely conferred gift or talent, but times have changed. Removed from the moorings of grace and favour bestowed by another, it has become a passing thing, defined by the insecure moment. Henry VIII, John F. Kennedy, and Tony Blair all exuded the charm and magnetism we today call charisma. But the passage of time shows something less to do with grace and divine blessing, and more to do with personal need; an energy arising from something unresolved within that needs others to calm, feed, applaud, and love it.

Simon Parke is the author of Pippa's Progress: A pilgrim's journey to heaven (DLT, 2012).