All hail a vulgar entertainer: Francis Bacon retrospective

It used to look like death. Now it looks like life in abundance. And it certainly doesn't look like going away. Francis Bacon's art has survived to his birth centenary, or I guess it will, since that falls next year. So this retrospective at Tate Britain, which opens tomorrow and just squeaks into January, is a centenary show.

But survival itself didn't need proving. Since its appearance on the London art scene in the 1940s, attention has never drifted from Bacon's work. What does need marking is how our view of that work has altered. And it seems to me that its whole place has changed. Bacon no longer stands as an artist among artists, not even a very special artist. He won't be grouped with the School of London, say (Freud, Auerbach, Kitaj), or under Post-war European Figuration (Giacometti, Balthus). No, he now looks simply like an icon of general British culture. He's a familiar. You talk about Bacon as you talk about The Beatles or Monty Python.

When the composer Mark-Anthony Turnage entitled a piece of music Three Screaming Popes – referring to Bacon's well-known series of images by a nickname – you could see what was going on. A "refined" art was drawing strength and vitality from a more popular art. He might as well have called the piece Three Dead Parrots. And if an unaccustomed levity seems to have entered the discussion, that's no mistake either. Bacon has a very British mix of violence, comedy and bloody-minded big-heartedness. And perhaps you hadn't noticed how fond of animals he is.

Bacon's art is not a tunnel vision of horror, expressing the futility of the human condition or the special nightmare of the 20th century. And going to this retrospective, you shouldn't expect to be inching forward in agony through frescoes of the skull (to use a Beckettian phrase). You should expect your money's worth – and you'll get it. The art of Bacon is a variety bill. It's a hall of mirrors, a crooked house, a peep show, a ghost train, a circus, a limbo dance, a stand-up act, a piece of conjuring.

Its theatricality is obvious. Bacon's paintings are scenes, made of distinct stage areas, backdrops, doorways and assorted props and actors. His people are presented full on, usually centre-frame. I don't deny that those people are sometimes in a terrible mess. Everyone, on their first encounter with Bacon's art, gets an impression of car crash, bomb damage, burns, meltdown, slaughterhouse. The red paint and the open mouths, of course, encourage this response. But they shouldn't distract you from the amazing performance that's going on before your very eyes. Bacon is a magician, a quick-change artist. He brings off the most sudden disappearing and reappearing acts, fusions and transformations. The flesh slips, slurps, smears, flares, blurs, fades, evaporates, abruptly dematerialises. Legerdemain: you just can't see how it's done, how it moves from solid to film to spook to gleam to void and back.

All this "damage" is in fact animating. There isn't a corpse anywhere in Bacon's work. His savage treatment is an extension, an exaggeration, of the body's own movements, sensations, expressions. And though his use of oil paint gives him a more liquid language, it wouldn't be wrong to see him in the line of English graphic caricature, and the way it uses distortion, not only to play with likeness, but to inject energy and rub the nerves raw.

Yet, strangely, Bacon's bodies are both sensational and invulnerable. They're in an awful state – and nothing can harm them. Whatever catastrophe befalls their flesh, they're saved by their firm, curvy, bouncy outlines. They seem held within a mould. Often they look like inflatables. Or rather, they seem invulnerable because they are both flexible shape-shifters and sturdy thick-skinned creatures, who can always bounce back. They carry a double fantasy of survival, familiar from animation: total plasticity, total resistance. Another name for this is slapstick.

And so we watch them, on their stages, in action: shouting, racing around, on the loo, sitting chatting, buggering, blowing smoke, throwing up, shaving, turning a street corner, writhing on beds, lolling. Their human shapes are joined by others, and dance with them, elliptical forms that might be areas of spotlight, amoeboid blobs that could be shadows or pools of spilt drink, except the colours and tones are all wrong: they're more like thought bubbles, or ectoplasm.

Sometimes, Bacon sticks in an overt artificial device, a geometrical circle, a road-sign arrow, a lopsided cubical structure framing the action. These perform a focusing, pointing, intensifying function – look at that, feel that. They show how far Bacon is from purism. If the act needs one of these extra winks, nudges or double-takes, he throws it in. If not, not. He never plays with the language of painting for its own sake.

It's a surprisingly large and embracing art. Bacon's one of the few modern artists to do cars – see them racing across in the background like little Monopoly pieces. And there's his menagerie of animals, real and fantastical, from the monster critters in Three Studies for Figures at the Base of a Crucifixion, to monkeys, dogs, owls and bulls.

And somehow one leaves to this late point the primary fact that Bacon is a sumptuous, delicious colourist. I wouldn't call him a real explorer in colour, but he is a great decorator, a great maker of tastes, and the point is: the tastes are rich and sweet, the harmonies are major key. Again, it's a shamelessness, it's showbiz. He can do it and he does it. He doesn't have any puritan qualms about being gorgeous. He's a vulgar entertainer.

Francis Bacon, Tate Britain, London SW1 (020-7887 8888), tomorrow to 4 January. Martin Harrison's Francis Bacon: Incunabula is published by Thames & Hudson (£39.95)