Already there is talk of a film based on the life and unlikely fame of the Britain's Got Talent contestant Susan Boyle. It will doubtless tell how an ordinary Scottish spinster of 47 had always dreamed of being a singer, how she appeared on a Saturday night TV show, how the audience and judges laughed at first at her frizzy-haired frumpiness. Then she began to sing. That voice! The film will show how it brought nations together, how Susan reminded the world of virtues and goodness which have all but disappeared in the early 21st century.

We shall see how, in the words of a normally tough-minded columnist, Susan Boyle "broke the grip of this sneering world" and will hear of the lesson which, according to no less an authority than Alistair Campbell, her success offers to politicians: nothing works better in communication than authenticity.

There is, of course, another, possibly truer film to be made. It would reveal how a decent middle-aged woman with a nice but unexceptional voice was spotted by TV producers who knew that, just as reality shows need a bully, so talent contests require the ordinary person with a dream. Other contestants would be given something of a makeover for their appearance on the show; she would be given a make-under, her ordinariness pointed up.

Adventurously directed, it might show how a talent programme can be cleverly edited to suggest a greater degree of mockery among the audience and judges than in fact occurred, making the transformation from laughter to wonder once our heroine starts singing all the more dramatic. Her triumph, in this alternative version, would present that ultimate paradox of our times: authenticity, as created by the celebrity culture.

How the story ends remains uncertain because no one – least of all Susan Boyle, one suspects – knows which path she will follow. She might be a Real Person Celebrity, filling the role recently vacated by Jade Goody, or, having enjoyed her moment in the spotlight, she could return to ordinary life. Either way, she seems strong and sensible enough to make the best of whatever happens to her.

It is her blubbing, gullible fans who are the worry. They have been manipulated. Such is the need to pluck some reassuring moral fairy tale from our tawdry culture – the triumph of talent over the odds, of an ordinary person in a celebrified world, of 1950s-style goodness over contemporary glitter – that people seem to have gone completely mad.

Mob sentimentality is every bit as alarming as mob bullying. There is a whiff of extremism and violence to it. Behind the increasingly loony stuff being written about Susan Boyle is an unattractive conflation of disgust at the way the world is going and self-congratulation that ordinary people – that is, the writer – can still recognise what is truly important.

When a Hollywood actress announces that the singing of a talent show contestant made her "teary", she is reminding us all that she too is an ordinary person at heart. When Alistair Campbell attests to someone's authenticity, an even greater degree of scepticism is required. It is extremely odd that people who would normally not even see Susan Boyle are now praising her to the skies.

Why? Not because of her voice, surely. Singing in a pub or at a party, Susan Boyle would hardly cause a riot. It has been the clever marketing of her, followed by a crashing wave of mass sentimentality, which has established her as the perfect manufactured celebrity.

Shane Coleman is on leave