The Libertine - portrait of a grey, grimy and brilliant land

The England of The Libertine has been a on 15-year-long binge - a binge of drinking, and fucking* and every other kind of debauchery that its brightest and best could dream up. Suddenly, however, the "hair of the dog" has become ineffective and through the lens of director, Laurence Dunmore, you see a society abruptly awakened.

It is opening its eyes to a grim, grey and desperate land; even the gaudy decorations of the theatre are fading, peeling, corroding. But John Wilmot, the Second Earl of Rochester (Johnny Depp), the man who has always shone above the rest, is not prepared to turn his path towards righteous, restrained endeavour that fits the new era - will not, and perhaps cannot.

I've always thought of Depp as a pretty-boy actor (when I've thought of him at all), but he turns in a stunning performance here, book-ending the film with wry, searingly honest monologues in which the twitch of the corner of an eye speaks volumes. And he manages to be both awful, and awfully attractive.

Yet he is almost eclipsed by Samantha Morton, playing his protege, the actress Elizabeth Barry, who, however much she might have to play the whore in the wings, is determined on stage to be her own woman, and secure her own fame. The final scene between her and Rochester is a wonderful portrait of a woman who has fought for and achieved power - for her the power over the fickle, dangerous, but passionately loving London theatre mob.

John Malkovitch is powerful too as the King - the man who'd led the party when he was restored to the throne as a fresh-faced youngster, but who's now an ageing roue, seeking, like any leader on his way out, to secure his legacy. He, as much as a king can, loves his subject Rochester, and he wants him to deliver for himself, but like any father, knows deep down that the Earl will always go too far.

But the star above all here is the camera - the way it peers through the murk to focus on a greasy strand of hair, a goosebumped arm, a bottomless pool of mud. You can almost smell and taste this rough, barbarian world - yet it is a world that values culture, wit and learning, a world the dissects and analyses every catch in Ophelia's voice, inspects every line of a new play to find the one that rings true.

And the language of the film - the words of the earthy, blunt 17th-century street, of the rapier-fast wit of the aristocratic fop, and the orutund flow of the formal stage - is brilliant. (It is based on the play by Stephen Jeffreys, and it shows in a classiness and complexity seen in few movie scripts.)

There was really only one scene I thought didn't work - the orgy in St James's Park, or at least the orgy that Rochester imagines. It is far too tame, too Vaseline-lensed an affair for the imagination of Rochester, but then again the director had to get at least an 18-certificate for it.

That's a reminder that for all the claims of the moralists, ours is an age far more uptight and hung-up than later 17th-century England. And in fact overall The Libertine is by no means an explicit film. A great many sexual things are suggested, but it never - thankfully - gets anatomical; it doesn't need to.

The only other negative is the handheld camera work - spinning around a character in a slow circle is rather overdone, and the first-time director should immediately put away the technique of moving two characters in and out of focus as each speaks - very year-one film school.

Nevertheless, as a portrait of an age, and of a brilliant man who's bent on sticking his hand in ever fire so that the pain can tell him he is alive, this film would be hard to beat.

I seldom go to the cinema, but my recommendation would be that even if you only go to one film a year, go to this one.

*I use the basic Anglo-Saxon here because it seems appropriate in the context of this film. (If it offends you here, you really don't want to see it.) The film itself has very few of today's "obvious" taboo words, but it might well revive a few of the old ones.