Throughout the film you saw men whose chief intellectual achievement was the construction of an alternative morality in which their appetites would be unimpeachable. One man, fined for videoing naked boys insisted that he only had their interests at heart

There's nothing to be ashamed of being a paedophile" said a grandfatherly figure in Witness (C4) "The Devil Amongst Us". I think it would be fair to say that this is a minority view but are paedophiles really the kind of minority which fall within C4's remit? Several more strongly worded versions of this question anticipated the broadcast of Dea Birkett's film, in which she talked directly to paedophiles about their activities and attitudes, without restating the obvious - that paedophile activities are wrong and universally reviled.

At the beginning of the programme she described her purpose as being to "meet and confront" paedophiles, and most of the criticisms of the film centred on whether she carried out the second of those tasks with sufficient zeal.

If by confrontation you had in mind a televisual anathema, spat into the face of the interviewees then you would have been disappointed. She didn't lecture any of the men she talked to about the iniquity of their ways and she didn't insult them, to their face or behind their backs. But her tone made it clear that an aberration needed explanation and she may have judged, in any case, that these remarks needed no additional condemnation beyond that which emerged from the speaker's own mouths. Those who talked were very varied in their degree of menace - from the retired man (with two children of his own) who claimed that he had never acted on any of his powerful desires to the former member of the Paedophile Information Exchange - a practised apologist for his urges - whose press officer demeanour became a bit ruffled when Birkett put the hard question: "Is it possible for a four-year-old to consent to sex with an adult?"

Birkett didn't quite press the question home but she let you see the flutter of trapped panic which it generated. At another point she explored the case of a Bournemouth scout master who, despite a conviction for sex offences against young boys, had set himself up as a charity worker for child prostitutes. Those seeking help were told to ring a number which just happened to be that of his own home. Birkett's film wasn't confrontational in any conventional sense here - no Roger Cook melodramatics, just a series of quiet revelations which exposed his prevarications and half-truths. : "For a child," he said, "the ultimate sexual thrill would be to play naked and be photographed or videoed naked... it fills a child full of confidence and goodness. It does them a lot of good." He even had an NSPCC sticker.

It didn't help, though, that the representation of those opposed to paedophile activities was almost as ugly. The Bournemouth case was followed by a detailed account of the man's harrassment by a local group of vigilantes, who had attacked the family home and even torched the car of a friend who had visited there, a visit that made it - in the deranged militaristic jargon of the conspirators - "a legitimate target". One of the instigators of this attack, a boy's football coach, had been jailed for the deed. Had he not been, he told Birkett, his gang was planning to kidnap the man, take him to a local forest and "nail him to a tree".

In comments to the press the programme makers cited this particular sequence as if it supplied a balancing factor to the unhindered explanations and justifications seen earlier. In fact it did just the opposite - making the paedophile appear as victim rather than victimiser. Birkett was right, I think, to argue that bricks through windows and local hysteria are an unworkable response to this threat. She included one telling case history in which a young boy had been traumatised by the arrival in his village of a convicted paedophile, not because the man in question had done anything but because the mother's warnings about the "child molesterer" had terrified him. By giving so much time to such extreme symptoms of the case against, though, and by excluding any account of the damage that could be done to notionally "consenting" children, Birkett undermined her project of dispassionate inspection.