The Weekend's TV: Digging for Britain, Fri, BBC2<br/>Crusaders: Back from the Dead, Sun, Channel 4<br/>Appropriate Adult, Sun, ITV1

Atrocity has a half-life.

On BBC 2 on Friday night, Dr Alice Roberts showed you the skeletal remains of a small baby, possibly murdered, and the sight aroused not much more than a scholarly curiosity. Last night, similar evidence of violent and brutal killings was laid before us on Channel 4, and so dispassionately detached from the human suffering involved were we assumed to be that the film included slow-motion reconstructions of the moment of death. And then an ITV drama merely alluded verbally to an act of appalling cruelty and the mind flinched from the touch like a snail's eye. The first two instances involved archaeological research into Roman Britain and a sacked crusader fort. The last involved the dramatic archaeology of Appropriate Adult, scraping away at the odd relationship between Fred West and Janet Leach, the woman appointed to act as a representative of his interests.

Forensic archaeology played a big part in West's eventual conviction, but no one would dare do with those bones what television regularly does with the remains of more distant victims. They haven't yet passed from the status of human relic to scientific curiosity. Once that has happened, though, it's open season, as Digging for Britain (a survey of recent archaeological discoveries) reminded us. The discovery of the skeletons of 97 babies, buried beneath a Roman villa, was actually featured in a previous series, but Roberts had returned to the issue, once again bending over a tiny ossuary, arrayed on black cartridge paper like the contents illustration from a construction kit. The cut marks detected on an infant limb need not have been evidence of murder, we were reassured, but might have been evidence of a primitive medical procedure intended to save its mother during childbirth. Last year, the hypothesis had been that this was a Roman brothel disposing of the inconvenient by-product of the business. This year that theory has had to shuffle over to share space with the idea that the site was actually some kind of maternity hospital. Nobody knows either way, and the bones won't say.

Crusaders: Back from the Dead, the second of a short series about forensic archaeology, was able to be a little more specific about what had happened to the original owners of its bones. That's because they were discovered in the destroyed remains of Jacob's Ford in Israel, a crusader castle that fell to Saladin's army in 1179. Muslim chroniclers had recorded the principal events of the siege and the skeletons themselves were far more explicit, hacked and carved in ways that preserved some trace of the fatal blows. There were skulls with slices cleanly pared off, forearms ending in neat truncation and collarbones distinctively notched by triangular arrowheads, all evidence of the desperate battle that followed the undermining of the castle wall.

It wasn't exactly a model of white-coated reserve in its science. No programme whose roster of experts includes someone called Pete "Buzzsaw" Holland (a "medieval martial-arts instructor") can be accused of over-sobriety in its presentation of the facts, and they extrapolated from the basic forensic details with a certain amount of dramatic liberty (how, for instance, could they possibly know the sequence in which four different injuries were inflicted?) It owed as much to the historical school of Jerry Bruckheimer as it did to that of Steven Runciman, but was often fascinating all the same, a reminder that there was a time when the suicidally fanatical religious zealots had crosses on their tunics, not crescent moons.

Appropriate Adult, Neil McKay's drama about Fred West, did this week what I thought it had failed to do last, which was to more closely question how Janet Leach became so bedevilled by the man she was representing. It was a far messier episode than last week's, full of uncomfortable ambiguities of tone and unresolved feelings, but the performances were up to it. As Fred, Dominic West pulled you in with what looked like sincere remorse and then shockingly revealed another flash of calculation. And Emily Watson disintegrated in an entirely believable way, suddenly realising how compromised she'd become. It was, I'm sure, a decent instinct that led the makers of the drama to conclude with images of the Wests' known victims. But it was a mistaken one. These women hadn't asked to be part of this story in the first place, and it felt wrong that they had no choice about their enlistment here.

t.sutcliffe@independent.co.uk