TV

"It is sometimes difficult to pick out the thread of fact about the mamba from the tangle of fiction", said Mark O' Shea, an English herpetologist, in To The Ends of The Earth (C4) . Most sane people, if told about a tangle containing a black mamba, would walk swiftly in the opposite direction but herpetologists are not as other men. We already know this because last week - as part of its continuing commitment to the serious documentary - ITV brought us The Ten Deadliest Snakes in The World (based on an entry in the Lett's Schoolboy Diary 1967). This was a very funny programme in which an Australian man travelled around poking poisonous reptiles and saying "Gosh! Isn't she a beauty!". "Black Mamba" wasn't quite as much like a Fast Show sketch but it confirmed that the normal rules don't apply to these people. They don't even use the English language in a way that is readily recognisable. "It's mildly venomous but perfectly harmless," said O'Shea at one point, clutching a writing length of electrical flex. My own definition of "perfectly harmless" would include objects such as a banana (cautiously peeled) or moist kitchen roll but it is not a phrase that would ever find itself in conjunction with "mildly venomous" (and there's no point in even starting on the discussion about whether mildness is a quality that can sensibly be attributed to venom).

O'Shea was in South Africa to catch Black Mambas, partly out of stamp- collecting completism (he'd never trapped one before) and partly because you need Black Mamba poison to make Black Mamba antivenom. We discovered that this works because one member of the expedition was bitten, fortuitously for the director, at the very moment when his film was beginning to flag a bit. This allowed him to reinforce the narration's repeated assertions of extreme danger with exciting footage of a nighttime dash to the nearest hospital, and a miracle recovery from coma to wisecracking good health. It also made the final capture, in which two men tried to coax a large mamba out of a tree, rather more exciting than it might otherwise have been.

Even if you don't believe that "once you've seen one snake you've seen them all" (as O'Shea wearily characterised the layman's attitude) there isn't a great deal of variation in film of them being wrestled into a sack. Roger Finnigan's film ended, intriguingly, with an unexplained sequence in which O'Shea peered excitedly into a bush and said "Aha. Fresh faeces! He's definitely been here. That is fresh, it's really strong". The director's attitude to his subject's safari-shorted machismo had never entirely come into focus during the film that preceded this enigmatic last word - and it did cross my mind here that we were being invited to think that the substance in question might have come from a bull.

The War Machine (C4) promised more schoolboy pleasures, with a film about the West Freugh bomb range, a remote stretch of Scottish beach where the Ministry of Defence goes to try out its new toys. It promised it, but did not deliver - because very long sequences of the film consisted of men waiting for clouds to clear or staring glumly at bits of machinery that hadn't worked properly. Presumably the thrill of gaining access to the Defence Evaluation and Research Agency was so intoxicating that nobody could quite bear to admit that what it was actually permissible to film was rather dull - even if, to be fair to the series, the tedium is an accurate reflection of the job.

The series seems to feel a bit guilty about its fascination with weaponry, beginning each episode with a sequence in which everything happens in reverse - as if showing film of a Harrier jet coming into land backwards would somehow nullify the glamour of military hardware. But that doesn't stop it from relieving the boredom every now and again by slipping in a quick montage of slow-motion weapon releases and high-explosive fireworks (even if the weapons in question bear scant relationship to those actually under discussion). I would uneasily have to confess to being part of the target audience for a programme like this - but the series gets no closer to the bullseye than the endlessly malfunctioning weapons it profiles.