Anyone left vaguely unsatisfied by the sub-Cosmo foreplay of The Good Sex Guide can swap it for the hardcore anthropological approach of THE SEXUAL IMPERATIVE (9pm C4). Having seen how the birds and bees do it, the last in this fascinating series brings the human animal into the picture. Is divorce so unnatural (asks the female Redback Spider, who kills the male before you can say 'post-coital tristesse')? How altruistic is romantic love, and are we the only creatures who indulge in recreational sex? The answer to that last question is no: the chimps of central Zaire make Red Hot Dutch look like Blue Peter, and the only distinguishing human characteristic appears to be the ability to fantasise - 0891 numbers as the pinnacle of human sexual evolution. And an even more shocking revelation is left to the end. The voice describing these scenes from nature's version of Salo belongs to that nice Hannah Gordon.
THE ESSENTIAL HISTORY OF EUROPE (8pm BBC2) also ends its run - in (where else?) Belgium. It is hard to imagine the rise of Belgian nationalism. If the people interviewed here - a wry, unassuming and likeable bunch: 'the product of non-identity', according to one - are anything to go by, there is a lot to be said for being invaded and occupied countless times over the centuries.