Last Night's TV: Life After People, Channel 4. Graham Hill: Driven, BBC4

Imagine our planet without people, an Earth from which humankind has been eradicated, whether by nuclear warfare or a meteorite hit or perhaps just a really, really virulent strain of bird flu. Without dwelling on the cause of the annihilation, Life after People presented a vivid picture of the aftermath, inviting us to take a leap of the imagination with the help of a solemn, portentous voiceover and background zither music those prerequisites for any documentary examining the end of the world as we know it.

"This film explores how long it will take before buildings collapse and roads become overgrown," said the narrator, gravely, and I could almost hear a loud hurrumph from viewers who feel that such a scenario has already come to pass in certain neglected parts of the world. But within a few people-less years, Belgravia and the Upper East Side would be looking like swathes of Croxteth and the South Bronx already do with people; vegetation sprouting through the tarmac, litter blowing down the streets like tumbleweed, derelict dwellings with broken windows, dogs running wild, and not a policeman in sight.

The first notable thing that would happen after the demise of humanity is that lights would start going out. About 70 per cent of the world's electricity comes from the burning of fossil fuels, and there would be nobody left to burn them, or to maintain wind turbines. The last illuminated place on Earth would be the south-west of the US, where for a couple of years the Hoover Dam hydropower plant could continue to function perfectly well without human input. So said the facilities manager Bill Bruninga, and I could only hope that his boss wasn't watching, and thinking 'so why are we paying the sonofabitch?' Whatever, the end of Homo sapiens would be marvellous news for fossil fuels, the ozone layer and fish. In some ways, Life after People offered a utopian vision of the future; shame about the extinction of the Green Party.

The programme-makers had done their homework, interviewing scientists galore, and visiting Prypiat in the Ukraine to see what happens to a vigorous city after 20 years without anybody in it. Prypiat was evacuated after the Chernobyl disaster and has since been reclaimed by nature. As the narrator said, "great cities have only a tenuous grasp on their surroundings". Without pumps to expel water from their subterranean rail systems, London and New York would flood from the bottom up. In the Hollywood version of this vision, only Tom Cruise, Cate Blanchett and a cute blond child would remain, though I dare say they'd run into Morgan Freeman sooner or later.

Without Tom and Cate to start repopulating the planet, wildlife would take over. Domestic pets wouldn't last long, but birds would prosper and cats would develop wings. Some of this was informed speculation, some of it not even that. Nobody knows what would happen to zoo animals, for example. In all probability they would wither and die behind bars, but in Life After People some of them escaped, facilitating computer-generated footage of lions padding along city streets. The programme considered what the world would be like a day, a year, 10 years and so on, up to 10,000 years after the end of humankind. All evidence of human civilisation would eventually disappear, although I'm sure there would be left some small trace of Freeman.

I think it was Charles de Gaulle who said that "the cemeteries of the world are full of indispensable men". His point was that there is no such thing as an indispensable individual, and the strangely comforting message of Life after People was that the same goes for the human race as a whole. That said, some people leave a bigger imprint than others, among them the motor-racing driver Graham Hill, the subject of the affectionate documentary Graham Hill: Driven.

Hill died at the controls of his own light aircraft in November 1975. He remains the only man to win the Formula 1 Drivers' Championship, the Indianapolis 500 and the Le Mans 24-hour race, and he was a five-times winner of the Monaco Grand Prix, so the legend would be secure even had he not been an incorrigible showman. This programme did not dwell too much on the flipside of that showmanship. He could clearly be horrible both to work for and to live with, and a decidedly loose interpretation of his marriage vows to the long-suffering Bette was casually dismissed with that feeble euphemism, "he had an eye for the ladies".

However, he undoubtedly added tremendous charisma to motor-racing's most charismatic age, and death in his mid-forties not even dreaming that he had fathered a future world champion in his quiet teenage son, Damon at least fixes him in the collective memory as a middle-aged, Dick Dastardly-lookalike, with a rakish Terry-Thomas moustache. It is hard, as with so many men of speed who died young, to imagine him in his dotage, although I suppose that's scant consolation to his widow and children.

b.viner@independent.co.uk