Culture: Never trust a politician who speaks from the heart

If Boris Johnson loses London's mayoral election on Thursday, his supporters will lay the blame squarely at the door of Lynton Crosby, his Australian campaign manager. By all accounts, it was Crosby's idea to suppress Boris's natural ebullience to make him seem a more serious candidate.

The issue of whether politicians have to remain "on message" to win elections does not just apply to the mayoralty. One of the criticisms frequently levelled at Gordon Brown is that he is too tightly wound. He lacks the warmth and spontaneity to connect with people that more natural politicians possess. Harold Wilson had it; Ted Heath didn't. Bill Clinton does; Hillary doesn't.

This question was explored in depth in The Absence of War, David Hare's play about the 1992 General Election campaign. The central character is a political leader called George Jones, clearly based on Neil Kinnock, who is constantly at loggerheads with his staff because of his reluctance to rein himself in. Like Kinnock, Jones's idea of campaigning is to leap up on a soapbox and set out what he passionately believes in.

In the aftermath of Labour's defeat in 1992, many people blamed Philip Gould, the campaign manager, for staging a triumphalist rally in Sheffield a week before the election, showcasing Kinnock's exuberance when it might have been better to keep it under wraps. In The Absence of War, Hare takes the opposite tack, attributing Labour's loss to the campaign team not allowing Kinnock to be himself enough.

So, should candidates for high office rely on their natural instincts or do what they're told? Perhaps this is a false dichotomy. The most successful politicians are those who speak from the heart and remain on message at the same time. I don't mean they're capable of giving the impression they believe in what they're told to say in order to win elections – I mean they really believe it.

The political theorist David Runciman, in his forthcoming book about political hypocrisy, argues that politicians such as Neil Kinnock are preferable to those like Tony Blair precisely because they are capable of saying one thing and believing another. In his view, this is better than being a hollow man, tailoring your beliefs to suit the latest fashion

This chameleon quality was summed up by Robert Musil in The Man Without Qualities: "The most coldly calculating people do not have half the success of those... capable of feeling a really deep attachment to such... conditions as will advance their own interests."