review

The invention of photography, which might have been expected to diminish the sacredness of representation by introducing a machine into the process, appears to have only strengthened it. Photographs aren't just pictures, they are relics - to be framed in silver, displayed, protected. Imagine a stranger defacing a snapshot of your wife or child with a sharp knife and you are offered a sudden access to the superstition that surrounds these most mundane of objects. Photographs are produced in astounding, industrial quantities, but they remain uniquely charged, a piece of ordinary, everyday magic.

Even on television (a medium notionally superior by virtue of its movement) photographs work - the powerful emotional effect of freeze-frame derives from the fact that, before your eyes, film is converted into photograph and the nature of your attention changes instantly: this moment, it is implied, will repay your scrutiny, can be made to sum up the flow of preceding images, none of which remained on screen for long enough to be truly looked at. The stillness is an accreditation, conferring on the picture an aura - sometimes entirely synthetic - of memorability. While the film moves, you are in an imaginary present, but the instant it stops, you know that the moment has passed and a nostalgia rises within you.

Photographs are also commodities, as Under Exposed (BBC2) reminded you. In a programme introducing the BBC2 Photography Project, Muriel Gray introduced you to several collectors of photographs, from the mercantile to the manic, every one of whom had been touched by the supernatural nature of the form. "For that moment, you're reliving that person's life," said the woman who specialised in collecting wedding photographs, rescuing them from house clearances and jumble sales. Her appetite for vicarious celebration was shared by a young man called Stephen Bull, who had amassed his own collection by asking for unsold photographs taken by staff snappers in holiday camps and theme parks - on his bedroom floor he unpacked a slithering landslip of strangers' happiness - or at least strangers putting the best possible face on their unhappiness.

Another man had used the money he earned from dealing to amass a collection of Irish historical photographs, irrefutable evidence, he insisted, of colonial oppression. You wondered, looking at these large gatherings of policemen, complete with wall-tumbling battering rams, why they had been taken in the first place. Was it pride in the work, or just an irrepressible impulse towards documentation? Either way, the impartiality of the mechanical witness meant that almost 100 years on, the images were being called for the prosecution.

As they were in Kavanagh QC (ITV), in which snapshots of a drugs bust were flashed around by prosecution and defence alike. Had I been defending the low-lives concerned, I might have had something to say about the fact that the heroin, held up triumphantly by the customs officers, looked suspiciously clean for an object that had supposedly just been retrieved from the viscera of a decomposing pig. But Kavanagh's opponent, while fighting on all fronts, had missed this tell-tale detail. Despite dire threats to Kavanagh's family, the baddie went down, defeated by the wily courtroom skills of our grizzled hero.

Kavanagh has a back-story to provide heavy relief from the long stretches in court - a running tension over his dedication to work and his detachment from family life. This is, to say the least, a little desultory in its nature. Last night it took the form of missing his son's birthday party, a sin for which he later atoned by some last minute fatherly advice over a wayward girlfriend. A glass of champagne, a bit of paternal sympathy and the son was all rueful resolution. His wife, meanwhile, has landed a demanding job with a hospital trust, which seems to limit her ability to give him grief over his long hours. If that's family dysfunction, I'm Princess Diana.