King Lear, Swan Theatre, Stratford-upon-Avon

Declan Donnellan doesn't half believe in jumping in at the deep end. This Lear announces the start of the Academy, the Royal Shakespeare Company's long overdue training arm. Its actors have just left drama school, and their first professional production (in most cases) includes 10 weeks' rehears-al and an international tour. Casting one of the greatest plays in our language, a play about age and loss, with youngsters is daring, if not simply crackers. But, though these actors are stretched, technically and emotionally, to an excruciating degree, the result is far better than one might have thought.

If no one has a voice of particularly limpid beauty, neither does anyone act as if blank verse might bite – which is more than can be said for some of the RSC's far more experienced actors. Lear himself is played by a black actor, Nonso Anozie. Though no fan of colour-blind casting, I was not troubled by Anozie, who has a majestic manner and a big bass rumble to go with it. And perhaps here the fact that Anozie is black, while the actresses who play his daughters are white, is symbolic of Lear's almost schizophrenic alienation from them and from reality. Anozie also has a somewhat babyish face, which is used to very good account in the mad scenes, as when he accidentally knocks poor Tom to the ground and looks at the still, silent figure with fear and bewilderment.

Some of Donnellan's other ideas work far less well. The actors perform in evening dress (the women in black) on a bare stage, which is OK, but the Fool and Kent and the Gloucester brothers are stuck with characterisations that do them and the play no favours. A failed night-club com-edian, the Fool, with brilliantined hair and a glittery jacket, is not only a trite conception, but is out of place in this play about brute nature. And Kent, as a high-stepping silly ass, has none of the character's dignity and tenderness.

Meanwhile, Edgar and Edmund are a very odd pair indeed. The good brother enters cartwheeling and gleefully slashes at imaginary enemies with a stick, his face so striped with mud that, when he decides to "be-grime'' himself as Tom, he needn't bother. Edmund, meanwhile, is slow of speech and passionless. The contrast between vitality and calculation looks more like idiocy and phlegm, and the final duel (for which Edgar creeps in late, like a naughty schoolboy) doesn't stir the blood.

The production's Cordelia is a striking one. Kirsty Besterman shines in the role, with her regal bearing and crisp delivery. A very fierce Cordelia (logically enough for one so righteous and so young), she turns the shame her father wishes on her into a trophy. In sum, then, this Lear is a Good Thing – though the ones who'll be really pleased by this choice will probably be the Academy players of next year.

To 19 Oct at Newcastle Playhouse (0191-230 5151), 23 Oct-9 Nov at Young Vic Theatre, London SE1 (020-7928 6363)