Why I turn on to the Christine and Tara show

There will be few married men whose privates don't contract like a slug under salt when she does her act

With uncharacteristic cunning, ITV has scheduled a particularly trivial-minded reality game show for the days leading up the first anniversary of the attack on New York. As we brace ourselves for an orgy of documentaries, which will reveal in ever grimmer detail what we already know, there is the perfect daily escape in the form of the carefully edited adventures of small group of semi-celebrities living in a camp in Australia.

What is intriguing about I'm a Celebrity – Get Me Out of Here! is, oddly, not the fame of its participants but that it is genuinely informative, possibly even educational. All reality TV, however vapid and manipulative, provides some kind of snapshot of the world outside: lock a few strangers together for any length of time and record their interaction on camera, and all sorts of half-hidden cultural hang-ups and prejudices are eventually revealed. The least interesting programmes – Big Brother and Survivor – select their participants from a narrow age-band and, as a result, are only of interest to viewers in their twenties, sociologists and voyeurs.

The best, like Castaway, dispense with the idiotic and rather unpleasant game-show element, take a mix of ordinary people and watch how they co-operate or fall apart under difficult circumstances. Celebrity versions are different. Here we watch people whose public personae are vaguely familiar. Because they already have a reputation, they are not influenced by the threat or promise of celebrity as a result of the programme. Above all, issues of class and age become unimportant: in Celebrityville, everyone belongs to the same social grouping, the fame elite.

So, perversely, what is currently on show is the purest form of reality TV. Without the trappings of public life – chat shows, gawping idiots asking for autographs – the participants are unable to retain their usual self-protective veneer. Soon we find that we are watching social archetypes trying, with limited success, to get along under difficult conditions.

What emerges? Firstly that people in their middle years are more interesting than those in their twenties. Here, even the oldies who are particularly dreary, bossy or self-obsessed are somehow flawed in a more complex, intriguing way than their younger, more attractive competitors.

So two of those who have been appearing on our screens, Darren Something and Nell Someone, have been of essentially ornamental interest. He, a dime-a-dozen media bloke, has been camping it up eagerly for the camera and has quite rightly been voted off. She sits around looking pretty and her sweet, empty looks are so adorable that she must be one of the favourites to go the distance.

The others are also distinctly recognisable. Uri Geller, the friendly nerd, and Nigel Benn, the bluff sportsman, have unsurprisingly been given their marching orders. Rhona Cameron – rumoured to be a comedienne – is a type to be found in most offices, a chippy outsider who is torn between her desire to express her differentness and her need to conform.

It is the other three who provide the programme's real dynamic and who the more sophisticated viewers must hope will reach the final jump-off. Christine Hamilton represents a generation of newly empowered, highly motivated and utterly ruthless women of middle age and class. Down the years, they have discovered that the way to get on is to appear amenable, a thoroughly good sport, while pursuing their own agenda with a will of iron. There will be few married men in the country who do not wince and feel their private parts contracting like a slug under salt when Christine does her sweetly reasonable act.

Poor old Tony Blackburn is suburban man personified. Quiet, slightly scared, desperate not to make a fool of himself, Tony has, in the end, allowed the resentment and jealousy of Mr Ordinary to reveal itself. "She's a stupid little rich girl," he murmured daringly as Tara Palmer-Tomkinson burst into tears once more. "Bugger off and give us all a break." All we needed was a set of net curtains and a privet hedge to complete the picture.

As for the stupid little rich girl, she has made and saved the programme almost single-handedly. Suddenly I see the point of this gloriously original party girl. Unlike the other contestants, who have huddled together in bitchy little alliances, she has gone her own way – childish, difficult, egotistical but incomparably funnier and more charming than the rest put together.

Of all the people I never thought I would spend time thinking about, Mrs Hamilton, Tony Blackburn and Tara Palmer-Tomkinson would come near the top of the list. Yet, as Career Woman, Robin's Nest Man and Party Girl, they have helped me understand our confused and fascinating culture as well as any work of sociology or earnest National Theatre play.

terblacker@aol.com