But what was said was less remarkable than the manner of its saying - dispassionate, detached, precise. Though the interview had been edited to leave nothing but answers, though there were elisions that hinted at halts and false starts, there were no detectable signs that this testimony had been a wrenching experience. It was like watching social workers describing a particularly unpleasant case, composing their features into a decorous, professional sorrow. Here, though, the case-workers were also the victims, cataloguing a lifetime of insanely twisted domesticity without emotion or hesitation. As children they had had to turn the television up to drown the sound of their mother having sex with strange men, relayed by Fred's home-made bugging system. As children they had been taught that there was no distinction between love, obedience and the sexual gratification of their parents. As young adults they laid it all before you without reluctance or distress.
They also seemed unaware of the contradictions in what they said - the acknowledgement that they envied other children's lives, sitting alongside the insistence that they could not tell how strange their own was; the description of extreme maternal violence alongside the conviction of their mother's innocence. "When she started hitting us I felt she found it hard to stop," said Stephen. "The most annoying thing was if she was hitting one of us she used to do us all, because she'd be in the mood for it," added Mae, picking up the tale with a rehearsed ease. Even when speculation brushed against the unspeakable - the things that had been done to others - there was barely a tremor: "I don't know whether that's his first experience of cutting up," said Mae, recalling that Fred West had been required to butcher pigs when he was a boy. You felt by the end that you had witnessed another murder - emotions killed off and buried so deep that they might never be disinterred. Ian Studdard's film, spare and adorned only with deceitful images of snapshot happiness, made no error of judgement - except, perhaps, that it had been made at all.
Modern Times (BBC2) had offered infinitely sunnier matter earlier in the evening, with Lucy Blakstad's portrait of Brockwell Lido, an oasis in the urban desert of South London. Her film was full of lovely visual accidents - an old swimmer wading out of the bottom of the screen as a beach umbrella in the background suddenly flapped in the wind and subsided, like a sea-bird rearranging its wings; a pair of sunglasses swinging like a pendulum through clear blue water to the bottom of the pool; a swimmer cleaving towards you underwater, feet breaking the carpet of quicksilver formed by the surface. So many accidents, in fact, that it soon became clear that you have to earn such luck.
Her film, an undressed anthropology in which sun-warmed swimmers let you into their lives, was beautifully composed - splashed into raucous turbulence at times, more placid at others, so that the images lapped at you, lulling and rhythmic. It was a good subject to begin with - all varieties of human life attracted by the waterhole, from senior civil servants to dope-smoking Rastafarians, from lesbian lovers to laddish lifeguards - but you were left with the feeling that Blakstad could make a film about a multi-storey car-park and hold your attention.