King Lear, Royal Shakespeare Theatre, Stratford-upon-Avon

A magical new home, fit for a King

How would it work in practice? This was the question still hanging over the new main auditorium, the creation of which was the chief raison d'être of architect Rab Bennett's spectacular £112m revamp of the Royal Shakespeare's Company's theatrical complex in Stratford-upon-Avon. The answer, now that it's finally up-and-running, is like a dream, to judge from the performance of David Farr's searching, brilliantly acted production of King Lear.

The 1,040-seat venue resembles a magically enhanced and more intimate version of the Courtyard. This latter was the auditorium that was created up the road as an interim measure and a testing ground while the company converted the frustratingly cinema-like interior of Elisabeth Scott's 1932 art deco main house into a thrust-stage theatre where no member of the audience, now sitting on three sides of the acting space, would be more than 15 metres from the action.

I am going on impressions here, but the audience seems to wrap the action in a warmer embrace here than in the Courtyard, while the cubic space has the air of being taller and the stage wider in proportion to its length, thus answering (to some degree) the complaint by the RSC's founder, Peter Hall, that acting on a thrust stage gives an actor only two options: walking down the diving board and then back up it again. As regards the question of improved acoustics, you now sometimes feel that you are sitting in a marvellous musical instrument constructed of wood.

The fact that Greg Hicks is one of the greatest verse-speakers of our day makes this initial encounter with the theatre a never-to-be-forgotten pleasure. Resonating through the squashed-visor mask of his face, that voice can thrill with the flash of brazen heroism or with the serrated steel of scornful irony and sarcasm. From the moment when he false-foots the assembled court by entering from an unexpected angle through the audience, this Lear is a barbed joker who becomes the painfully moving butt of his own disastrous whimsy. The journey Hicks's Lear makes from defensiveness of parodistic mockery to the humility of naked feeling more than matches, for my money, Derek Jacobi's performance at the Donmar.

I wanted to see how the production would strike someone sitting right at the extreme end of the upper circle, so I made the climb up there from my excellent seat in the stalls. It's a lofty perspective – you are higher even than the grimy, cracked window that surmounts Jon Bausor's excellent kingdom-as-crumbling-warehouse set. But you're on top of the proceedings in more ways than one. You don't feel, as in Edgar's aerial speech, supposedly from the top of Dover cliff in the play, that the fishermen "appear like mice". And the walk up through the corridors and walkways brought home how, though the new building now has the ambience of a sleek cruise liner, it's different in one key respect. You are free to walk where you will during the interval in a theatre that binds everyone together into a democratic whole.

To 2 April (0844 800 1110)