The Weekend's Television: The Thick of It, Sat, BBC2<br/>Ray Mears's Northern Wilderness, Sun, BBC2

It's an odd and often depressing business writing notes about a comedy show. When the comedy doesn't work you end up with a meagre stack of descriptive redundancies that are only there because you wanted to show willing.

If there wasn't anything noteworthy, after all, there shouldn't be any notes, but one likes a few straws to clutch at when you're attempting to convert a 30- minute waste of time into a three-inch waste of space. When the comedy is terrific, though, you scribble away like crazy but can often end up feeling like you've been putting butterflies into a killing jar. Your pinned collection of highlights lacks the very thing that made them catch your eye in the first place. Anyway, The Thick of It is back and is back in terrific form, and I tapped away furiously while watching it, slightly dazed by the fact that every other line seemed worth quoting. Now that I come to quote it, of course, some of the colour has gone, but believe me when I tell you that it's worth catching these things in the wild.

Wild is the operative word here, obviously, since everything in The Thick of It whirls around the gravitational pull of Malcolm Tucker's savagery. There are other good and reliable jokes in the show: the needling banter between Ollie and Glenn or the illusions, variously dimwitted or self-deluding, of the ministerial victims. But it's Malcolm who charges everything with electricity, even when he's not around. "Think of a thin white Mugabe," said someone, trying to prepare a novice for the shock of first encounter. And in Peter Capaldi's furiously paced performance well-written lines become something even better. On the page, "He's so dense that light bends around him" may not look that funny. On the ear, flicked aside lightly as if it's not even a punch-line, it's terrific. "I've got a to-do list here that's longer than a Leonard Cohen song," railed Malcolm, and you laugh partly because the metaphor is unexpected, but also because it's delightful to find that his spleen needs more raw material than he can actually find in front of him.

Rebecca Front plays the new minister, and plays her well, even if I found myself hankering just a little for an opponent that would give Malcolm a bit more of a run for his money. Perhaps that will come in later episodes, but for the moment the new incumbent is a fairly familiar cocktail of naivety and self-importance, and no match at all for Malcolm's five-moves ahead, street-fighting skills. Tucker, sensing a troubling residue of idealism in the new minister, gave her a brutal induction into the realities of promotion in a last-term government: "This is series 10 of the Big Breakfast," he hissed, "and you are the dinner lady they've asked to come and do the show." And then, to ensure her dependency and compliance, he dispatched her for a bit of local electioneering, carefully directing the photo call so that the candidate's name was trimmed by her shoulder into a mortifying caption. Staggering away from this carefully engineered public-relations fiasco, the minister is forced to cave in on her principled insistence that her daughter would be moving to a fee-paying school, thus preserving the party from the implication that the schools it has worked so hard to improve are all – as Malcolm furiously puts it – "knife-addled rape sheds".

The gearwork of the plot is beautifully articulated, but again and again it's the invention of the language that knocks a laugh out of you. There are great insults, of course ("You look like you've shat a Lego garage", "Have you been asleep in a box of straw like a Blue Peter tortoise?!" ), but also lines that take four words to get 40 words of description across. Warning the minister that she was about to walk into a media feeding frenzy, Malcolm told her, "They'll be all over you – like a pigeon on a chip." And Capaldi lets you know with the delivery that he hates pigeons, chips and novice ministers with equal intensity.

Ray Mears is everything that Malcolm is not – gentle, incorrigibly romantic about nature and perfectly happy when there's no human to torment (or even talk to) within a radius of a 100 miles. In Ray Mears's Northern Wilderness, he wanders around Canada's Boreal Forest, rhapsodising over sphagnum mosses and learning how to make doilies out of birch bark (I'm not making the last bit up). "You know you needn't fear the forest," he said reassuringly, but then – rather unhelpfully – he pointed out the bear claw marks on a nearby tree and a little pile of wolf poo, densely packed with the fur of some small creature that wasn't carrying a handgun. It's not the forest I'm frightened of, Ray. It's the hungry things wandering around inside it. Very soothing programme, but I think I'd still rather take my chances in Whitehall.