I realise it goes completely against the grain of the political and emotional moment, what with the new Prez and his team banking everything on Hope, but after seeing Fernando Meirelles' cop-out-filled adaptation of José Saramago's Blindness, I'd like to say a few words in vigorous defence of Despair.

The thing worth hating about movies like Blindness, besides the fact that its director seems way out of his depth, is that they create a nightmarish, lovingly detailed end-of-the-world situation - in this case, a sudden, inexplicable epidemic of blindness - and then abandon the courage of their convictions by permitting each character the tiniest slice of banal and completely unearned personal redemption, thus turning their movies into the worst kind of churchy, middlebrow nonsense.

It happened in Children Of Men as well. The best parts of that movie have to do with the awfulness of its imagined future, in which it seems that no children will ever be born again. As long as that dire prospect holds, the movie exerts a magnificent power. The minute there's a way out, in the form of a young, pregnant Virgin Mary figure, one feels the movie slackening, and its quasi-religious ending and the Christ-like sacrifice of the Clive Owen character leave the sceptical viewer gagging on his popcorn. (I should add I've seen the movie half a dozen times, and admire great tracts of it, albeit for largely stylistic reasons and its debt to Peter Watkins.)

Now, admittedly, I'm more likely to admire a movie that ends on a viciously downbeat fade-to-black than on some cheerful sunrise and a chorus of "Oo-ooh child, things're gonna get easier..." But really, is pessimism any less valid from an artistic perspective than optimism? If it is, then what does that mean for the paintings of Edvard Munch or Strindberg's dramas? I think that Ingmar Bergman, Fassbinder, Béla Tarr, Peter Watkins and Terence Davies might have a few words to say in defence of utter, uncompromised and undiluted misery. Are their works somehow lesser movies because they don't end with the spring buds blossoming in the debris and babies being born in war zones?

To say that despair and pessimism aren't commercial - and that's usually the argument - is to ignore the success of the Mad Max movies and the Matrix trilogy. The Birds was not a flop - even minus Hitchcock's planned final shot of the Golden Gate Bridge covered in crows - and Night Of The Living Dead and its sequel Dawn Of The Dead made millions even though George Romero never once compromised his bleak vision. The Mist was only made because director Frank Darabont insisted its dark ending was non-negotiable. On The Beach, Day Of The Triffids, 28 Weeks Later - all of these stick to their miserablist guns and often that's their primary virtue.

There are hard times coming. Look around you. I think we can take a little agony and despair in our movies. We're not children.