Last Night's Television - Life, BBC1; Murderland, ITV1; Race and Intelligence: Science's Last Taboo, Channel 4

Forgive me for revisiting last week's TV before last night's, but I still haven't got Question Time out of my system. What struck me most about the British National Party leader, Nick Griffin, was not the repugnance of his political views, which he tried to disguise, but his physical repugnance, about which he could do nothing.

Rabble-rousers of the far-right are quite often wolfishly or even non-wolfishly handsome. Oswald Mosley was a striking-looking fellow, as was the late Jörg Haider, the leader of the Austrian Freedom Party. Even Jean-Marie Le Pen, until he opens his mouth, might be mistaken for someone's kindly old uncle. But Griffin, fat and boss-eyed, looked like a caricature of a right-wing extremist, perhaps as P G Wodehouse might have imagined one of Roderick Spode's Black Shorts, as deeply unattractive to look at as to listen to. And whereas I wouldn't normally savage a man for his physiognomy, that's what he does so I think he's probably fair game.

As for those beliefs of his, the fact that he tried to temper them for the watching millions, denying this burst of Holocaust denial or that burst of repatriation rhetoric, surely shows how histrionic and unsupportable he knows them to be in intelligent, moderate company. Even some of the BNP faithful evidently felt that he should have presented the party's views more honestly, that he might as well, with apologies to the ovine community of Great Britain, have been hung for a sheep as a lamb.

All of which brings me to Rageh Omaar, the Mogadishu-born, Oxford-educated former BBC reporter now with Al Jazeera TV, who is just about everything Griffin is not: black, of course, as well as highly telegenic, eloquent, courageous, charismatic, and a reflection of much that is best about Britain. Yet in Race and Intelligence: Science's Last Taboo, Omaar dared to examine a question that on Question Time stayed hidden in the folds of Griffin's jowls – the notion that black people are genetically less intelligent than whites.

It is an abhorrent notion yet with some scientific credibility. James Watson, the co-discoverer of DNA, has expressed gloom about the future of Africa on the basis that "all our social policies are based on the fact that their intelligence is the same as ours, whereas all the testing says, not really". There are plenty of other illustrious scientists who support the view that there is a kind of global league table of intelligence, apparently with the Australian Aborigine at the bottom, and Omaar talked to several of them. But he found that their assertions are largely based on IQ tests that militate against the developing world, taking no heed of "wisdom, social intelligence and creativity". Moreover, in South Africa, where educational opportunities are no longer determined by race, such ideas are increasingly confounded.

This was a thought-provoking, important and indeed timely documentary, although it is rather dispiriting that Omaar felt the need to make it. He asked one contributor why such flawed scientific evidence should even be available to support racist ideology. The answer was devastatingly simple: because we live in a racist society.

After racism, let us now turn to the matter of sizeism. Or to be more accurate, inverted sizeism. I watched the generally excellent second episode of Murderland with a slight niggle that I couldn't quite place but eventually identified. Detective Inspector Douglas Hain (Robbie Coltrane) has lots of enemies. The head of vice doesn't like him, nor does the police psychologist, nor does the local porn baron, and there seems to be a possibility that he has killed his prostitute girlfriend with a kitchen knife, which is why he is obliged to retire from the force. Yet nobody ever refers to him being the size of a small van, which is disconcerting, because social sensibilities otherwise belong in the gritty urban landcape of Murderland much as orchids belong on icebergs. The bloodied corpse of the slain prostitute is seen frequently in flashback, but nobody calls the fat detective a lard-arse.

Maybe I am making too much of this, but it does seem a shame that we haven't moved on from the crime-cracking days of Frank Cannon, the private detective played by the Weeble-shaped William Conrad, who in the 1970s seemed to spend most weeks running through LA parking lots after villains half his size, invariably catching up with them. The same was true of Hain. When the murder victim's daughter, 13-year-old Carrie (Bel Powley), legged it to a phone-box, he was miraculously there in no time.

Even had this sequence of events been more plausible, it wouldn't have been the best chase of the night. That was provided by an elephant shrew giving the slip to a hungry lizard in the latest episode of Life, and I make no apology for reviewing this remarkable series week after week, because it is landmark television. Again we watched it as a family, this time marvelling in unison at the ugliness of the Madagascan aye-aye. But in the animal kingdom, ugliness comes with many redeeming features.