Last Night's TV - Getting On, BBC4; Harry and Paul, BBC2: The Secret Life of the National Grid, BBC4

A generous dose of the best medicine

It doesn't happen very often that we invent new ways of laughing at ourselves, but I think you could make a case that the awkward silence is a peculiarly contemporary mode of comedy. It's not that you can't find any antique instances of the humour of speechless embarrassment. It's just that it's only recently become one of the standard forms for which a sitcom can reach. It has its own associated visual style – that of hand-held documentary realism – and carries its own implication, which is that any programme that employs it is operating in that fertile (and upmarket) borderland between sitcom and drama. And Getting On – Jo Brand, Joanna Scanlan and Vicki Pepperdine's comedy about life on a geriatric ward – is a perfect example. It even has one of the style's most characteristic markers: a signature tune that is ostentatiously melancholy and distinctly retro (in this case Richard Hawley's "Roll River Roll"). Where a traditional sitcom tune would unleash the bassoons and brass and try to parp you into hilarity, this kind of theme song gives you permission to laugh ruefully – which will sometimes mean not laughing at all, but simply adopting an expression which sits somewhere between a grin and a wince.

None of this is meant to imply that Getting On is anything but excellent, only that it follows the trail blazed by a comedy like The Office, where the punchline often lay in the fact that a character couldn't think of what to say next and the dialogue dribbled to an excruciating halt. There was a textbook example here, in a scene where Pepperdine's odiously brisk Doctor Moore was sparring with a patient's relative over a course of treatment. Why isn't she being given Drug X, asks the anxious relative. Because it's not an appropriate drug at this point and I will make the clinical decisions, replies Doctor Moore, professional affront expanding like a lizard's neck ruff. Drug X is quite unsuitable for her current condition, she insists pompously. At which point, Sister Den (Scanlan) interjects to point out that the patient is actually being given Drug X and the scene ends in stammering damage limitation. Getting On is full of such embarrassments, beautifully acted and excruciatingly awkward.

There are more straightforward writing pleasures, too, last night mostly centring on a homeless patient with a perianal abscess, who arrives accompanied by an odour strong enough to discolour the curtains. "It's a kind of every-orifice cocktail," gasps Nurse Kim (Brand), blinking in the fumes as they undress her. "Can we just stop there and get used to that layer?" Then she pauses, distracted by a moment of nostalgia when it turns out that one of the patient's undergarments is a sheet of tabloid newspaper describing Dirty Den's webcam sex scandal (a story that broke in 2004). And if that sounds cruel, it wasn't – just an entirely plausible blend of black humour and grim reality, delivered with a fine grasp of understatement. Sometimes it's a beat or two before you even notice that a joke has been made.

Awkward-silence comedy has left its mark on Harry and Paul too, which is surprising really, since it's a bit harder to get it to work in a sketch show. But the running gag about the hapless middle-ager who's fallen hopelessly in love with the Polish girl at his local café definitely draws on a dynamic in which the humour lies mostly in what isn't said. Laura Solon is syllable-perfect as the contemptuous Pole, and Harry Enfield wonderfully glum as a man who can't give up hoping, despite knowing that things are hopeless. I'm always glad to see the establishing frame which tells you its coming, which isn't always the case in Harry and Paul, an odd mixture of running gags that still have legs and those that have long run their course. It's a question of taste I guess. "Parking Pataweyo", a cod-children's programme built around a Nigerian traffic warden, struck me as being only just funny enough for a one-off, and a recurrent sketch in which two old clubland buffers discuss the sexual orientation of celebrities is so unvarying in its script that even the energy of the comic acting can't revive it. But I can take any amount of the lubricious Italian prime minister or (a genuinely trenchant bit of social satire this) I Saw You Coming, which revolves around the endless gullibility of ladies who lunch. This week the character had gone into the spa business and was offering a novel activity he called "Detoxerboxercize". "I literally beat the crap out of you," he explained. His mark looked momentarily doubtful until he added the magic words: "It's good for releasing toxins."

The Secret Life of the National Grid delivers alternating current, too. Some of it is fascinating, such as the revelation that in the early days of electricity there was no common standard for supply, so that if you moved house you also had to change all your electrical goods, too. And some of it is so studiously banal that you want to do your bit for energy conservation by switching it off altogether. A long sequence in which three electricians discussed the undesirability of naked light bulbs was almost like a Harry and Paul sketch, though here the deadpan redundancy was unintentional. I am grateful to it, though, for indirectly leading me to the Pylon of the Month blog – a celebration of global pylon design which proves that no object, however unlikely, is exempt from human enthusiasm.