"In all important matters," he added, "style, not sincerity, is the essential."

It's the kind of quote that does Wilde's reputation no favours. He wasn't always as shallow as it suggests. Read The Ballad of Reading Gaol and you see style and sincerity welded to moving effect.

But he was, of course, onto something when he stressed the importance of style in matters serious.

As I am reminded every time Gordon Brown opens his mouth.

Brown can't fake style, and his attempts to do so are, I suspect, among the things that backfired for his party in the local elections.

By the time you reach his age, your personality is fixed, and you can't transform yourself into a cool, celebrity-hugging, down-with-the-kids kinda guy. Best to play to your strengths – of which Brown has many, if only he'd have the courage to be himself.

But what we get is a kind of schizophrenic jerkiness. In the middle of a glower, he suddenly remembers to smile, and the effect is disconcerting.

At such times, I miss Tony Blair, a fascinating figure in whom it was impossible to tell where the sincerity ended and the style began. But maybe this is a false distinction. By the end, Blair was perhaps long past the point where he could have made the distinction himself.

The actor Michael Sheen, who played Blair in The Deal and The Queen, appeared on The South Bank Show a while back, and showed a clip of Blair giving the 'People's Princess' speech, insisting that the crack in the PM's voice as he uttered the famous phrase could not have been faked.

I found myself at a party discussing this with a lawyer recently, who offered a further complication to the style-sincerity question.

"I sometimes get emotional when I'm talking in court," he told me. "And hear my voice crack. But just because the feeling is genuine, that doesn't mean I'm not also thinking, 'I bet that voice-crack went down a storm'."

Brown can't do the voice-crack and he can't do jokes. He can quote figures – Boy, can he quote figures – and that's what he tends to do when threatened.

In the days leading up to the election, the Today programme featured interviews with Cameron and Brown on successive days, coinciding with my morning drive.

Brown was painfully defensive. As he hunkered down and spewed out a burst of statistics, I found myself gripping the wheel all the tighter, tensing in my seat.

I identified with him, siding with him against the interviewer (It's not hard to side against John Humphrys), while in the back of my mind, memories stirred of harrowing job interviews and reprimands from angry school teachers.

The next day, Cameron leaned into the wind of Humphrys' assault, calmly rolling with the punches, at one point chuckling, "You are impossible", and ending with that traditional half-confession: "You might very well think that, I couldn't possibly comment."

It was very Blair, and as I listened to it I glided through my drive, cool and sunny as the breeze on a spring morning.

None of which is to say that we should vote for Cameron.

But it does at least give credence to Wilde's estimation of the importance of style.

awolstenholme@ywng.co.uk