In his excellent Swedish detective novels Henning Mankell lets you know all about his hero Kurt Wallander's insides - his hangovers, burger-induced diarrheal attacks, blood pressure issues and, in later books, diabetes - but nothing about his face. That, he told me, when I interviewed him a couple of years ago, is intentional, done to let the reader fill in the features. Our encounter had an odd effect, in my case, however: I now imagine Wallander as a lined, paunchy, laconic bloke with white hair - Henning Mankell, to be precise.

So physically, Kenneth Branagh was not quite right for me when he made his debut last night in the first of three adaptations of Wallander novels. He looked too, well, Ken Branagh. But after a few minutes that no longer mattered. Branagh's face betrayed all we needed to know of his detective's interior life. It wasn't Wallander who was physically sick in last night's story - that was the callow forensic psychologist's lot - but he looked sick: sickened at the macabre serial killings he was investigating, sickened by what Sweden has done to its youth, sick of his job and sick with worry about his father who, he had not quite realised, was dying of senility. Alzheimer's, Wallander Sr explained, cannot be “solved”. But nor, we were invited to con- clude, could the conundrum of Sweden.

Bookshops these days actually have sections headed “Nordic Crime” and the books beneath appeal to an atavistic British appreciation of battleship grey skies as well as a certain Schadenfreude that there are winters worse than our own. But Sidetracked, based on a later book, began with blue skies and a cornfield. Sweden looked warm and beautiful. So the landscape was not what I expected, but it was still refreshingly other, as were the Swedish ring tones on the mobiles and the Scandinavian idea of “squalor” (judging by Wallander's flat, derided by his daughter, Scanda-squalor equates to a British divorcé's idea of “pretty tidy”).

It was, anyway, under blue skies that a young teenager kickstarted the plot by immolating herself, only seconds after Wallander had announced himself as “police” (not polis, you note, the show eschews 'Allo 'Allo foreign accents). That the word police could be quite so incendiary to a teenage girl rightly troubled Wallander as he investigated the murder of members of the Swedish establishment. These, it turned out, were revenge attacks on behalf of virgins raped by an ex-politician, an art dealer and, crucially, a former police chief, the latter, played by Jon Laurimore with such cold, suave creepiness that “pure evil” for once did not look an overegged description.

“What kind of world?” Wallander asked early on, as he was told of seven-year-olds who cut off their thumbs and five-year-olds who scratched out their eyes. The tragedy of child abuse is used too often in fiction, but here it meant something. Seconds before his death, one of the victims watched himself on TV pontificating on Swedish decadence. Wallander did not pontificate, nor did it suggest the assassination of its prime minister 21 years ago was Sweden's original sin, but it did cause the viewer to ask questions about the link between permissiveness and social breakdown. This distinctly superior cop show is both spare and suggestive, and brilliantly acted.

To see a society in real meltdown you will have had to have watched Louis Theroux's journey last night to the city some call “Killadelphia”. Theroux's trips in the backs of police cars took him from addict to dealer to killer to corpse. It was a depressing tour streaked with black humour but Theroux seemed out of depth analysing what he saw. He is at his best getting to know and under the skin of his subjects. I am not sure if these more impressionistic, episodic films - next week the streets of Johannesburg, earlier this year San Quentin prison - quite work. Last night's documentary was sometimes only a little better than an episode of Cops.

I have no reservations anymore, however, about Channel 4's Animals in the Womb films. I say “anymore” because when I reviewed Extraordinary Animals in the Womb a few weeks back I objected to its puzzling lack of commentary. The producer was even more puzzled since there were voice-overs, although not on the preview disc I was sent.

Happily, my copy of Saturday's womb-with-a-view film was intact. The script that followed the gestations of a Neapolitan mastiff, a golden retriever and Chihuahua was excellent, too, containing within it history of natural selection and an explanation of how the wolf had, through human agency, launched 400 breeds of dog in just 15,000 years - “a reflection of humanity's amazing ability to tame the wild and mould it to its purpose”. That was one way of putting it. Forging a breed of dog, as in the Chihuahua's case, so small that it can give birth only by Caesarean section, seemed to me less amazing than cruel.

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