Sarah Palin's Alaska, Discovery Real Time/ Louis Theroux: Miami Mega Jail, BBC Two

Someone had moved in next door to the Palins. There was a camera shot of him, his face pixellated out. Apparently he was writing an exposé of the lady of the house. “I think it’s an invasion of our privacy and I don’t like it,” chirrupped Sarah Palin in that fingernails-on-a-blackboard voice of hers.

Sarah Palin’s Alaska was screened in the States towards the end of last year, where it was widely interpreted as an attempt to relaunch her political career. The series has now canoed across the Atlantic and taken up residence on one of those channels whose name sounds like an off-road vehicle. Its eight episodes find Palin experiencing the wilds of the state - hunting, shooting, fishing, stopping boys from sneaking upstairs to impregnate her daughters.

The baby’s diaper was changed on the snarling bearskin throw rugHer calculation seems to take a leaf out of the book of her near neighbour Vladimir Putin (whose country, lest we forget, is visible from Alaska). His vacation snaps depict him wrestling with mammoths, lassoing yaks and taking semi-automatic potshots at Chechens. Palin looked just as macho fishing the same waters as huge brown bears, whose aggressive display she greeted with a nauseating panoply of faked-up orgasmic squeals. The fact that her small children were dragged along for a date with danger made you pray anew that she never gets anywhere near a foreign policy brief. She soon spoiled the illusion anyway by going rock-climbing and getting chicken. “I don’t think I have been that challenged in a long time.” She’s presumably forgotten about this:

Watch Sarah Palin interviewed

Meanwhile back at home the baby’s diaper was changed on the snarling bearskin throw rug. A wall-mounted caribou looked on impassively. Various people called things like Truck and Trog, Troop or Trib or Troll wandered about, walk-on players in this risible woman’s delusional pitch for power. Alaska looked very fetching though. It was a bit like being on a spectacular holiday marred only by the worst travelling companion imaginable. Over the garden fence the reporter continued with his watchful work. “He’s going to be bored to death,” said the woman who had invited a camera crew in to observe her family and its activities, “if all he has to do is observe our normal boring family and our activities.” Tina Fey, you can retire.

You wish Louis Theroux were still making films about celebrities: he could give Palin a wry old kebabbing. Instead, his fascination for the extreme American underbelly continues. Miami Mega Jail finds him entering the penal system in Florida, in particular a prison facility where, for want of state funding, inmates on remand await trial while crammed into heavily overcrowded cells. Felons of every stripe are thrown in together. “You could be in here for stealing a bike,” one of them explained to Theroux through thick bars. “What’s your charge?” “First degree murder.”

I once watched Theroux at work in the flesh. He was making his film about Max Clifford. When the camera turned on him, it was like Superman in reverse. Uber-confident, Bafta-winning Theroux mutated into puzzled, geeky Louis. He seemed to inflate into an impersonation of himself, of the character whose eyebrows dance in that familiar array of facial exaggerations.

He doesn’t do that shtick any more. The stakes are too high when confronting paedophiles and religious maniacs and, in this case, mostly African-American males locked into a cycle of violent crime. Part pastor, part entertainer, Theroux went about his plaid-shirted work with a "but why would you want to do that?" look pasted discreetly across his otherwise poker face. Some inmates covered their faces anywhere near the camera. Others had their picture taken with him. The images supplied by the BBC leave a strange taste in the mouth. Who asked whom for the snap? Did the producer really say to a serial armed burglar, "Actually, we just need this pic for the publicity department"?

A performance of a different kind was required of him when he was ushered into one of the cells full of men who fight, maim and masturbate with equal lack of abandon. It was like entering a cage hung with cobras. He had to play brave. Inside these cells there is a ruthless code. The most powerful inmate rules by sheer force of strength. “GABOS,” explained one of them. “Game ain’t based on sympathy.” One puny-looking college-educated Hispanic survived his brief time in such a cell by sitting stock still on his bunk for 24 hours. Charged with attempted murder, he was thinking of entering a plea of insanity. If he isn’t now he soon will be. Every other time one of the impressively humane female guards walked by, an inmate would start "gunning" (that's taking advantage of himself). “How do you feel about masturbation?” asked one inveterate gunner when challenged. There was a beat while Theroux wondered whether he should share. “I think you should do it private?"