The theory of modern dress, presumably, is that if someone wears dark glasses or combat gear we are more likely to listen to what they say than if they wear a sheet. In Mitchell's new production, Apollo wears corduroys and a white coat and appears to work in a chemistry lab. Clytemnestra wears a floral-print dress, and her new bloke, Aegisthus, is a nightclub smoothie in dinner jacket and cream scarf. It could be the republican version of The Oresteia: the one without any majesty.
Of course if you wanted an authentic Greek experience you would have to leave your slaves at home, and probably your wife, too, and head off to an amphitheatre with only the elite section of the male population. On the way you would have to cast off any ideas gleaned from Christianity, the Enlightenment, romanticism, feminism, modernism or postmodernism. It is almost impossible to see a play through the eyes of an Ancient Greek. (It is hard enough for me to see a play through the eyes of some of my colleagues.) But we can be sure that, once there, distance was essential for grasping the plays' monumental scale.
The National has one theatre, the Olivier, specially designed for Greek tragedy. Mitchell decided to use one of the other two spaces available. Her Cottesloe production brings the Greeks up very close. I was sitting a few feet from Agamemnon's grave - a manhole, with red and white emergency tape around it and a video camera placed inside. Certainly, at this proximity, the pain can feel more immediate. When Clytemnestra stepped back from the grave, one of her stiletto heels squashed my foot.
We see the stylistic tension within the production from the first speech of this six-hour performance. The watchman is just a regular guy, pressing the veins on his temples and moaning about the boring nature of his job. His prosaic manner does not quite square with his description of the stars as a "glittering parade of lofty rulers". The power of Hughes's imagery fuses the two worlds of then and now in a way that eludes the production itself. The leading protagonists, in particular, find themselves caught between two acting styles, the elevated and the intimate, without finding authority in either.
The chorus fills in the history of the house of Atreus with the care of friends giving complicated road directions. When Anastasia Hille's Clytemnestra details the journey that the beacons of light made from Ida to Lemnos to Makistos to Saronis and Argos, a map is projected on to a back wall and torch lights point out those places, just in case any of us thought she might have been referring to another Ida, Saronis and Argos altogether.
Such a tone of patient explication extends from the bare bones of the plot to the big themes themselves. It was obviously bad news for Agamemnon to sacrifice his daughter Iphigenia to get a decent breeze for his ships. But lest we forget what happened to Iphigenia, her ghostly figure wanders, gagged, round the stage during Agamemnon. After his death, Agamemnon wanders round the stage during the second part of the trilogy. Just in case we still have not twigged what all this may mean, Apollo opens a Red Cross medicine box in the The Eumenides and we hear the voice of Ted Hughes reading from the Four Quartets and reminding us that time past, time present and time future are inextricably linked. Additional information is provided by the camera picking out pages of books: the writings of Tom Paine, a description of the hydrogen bomb and a dictionary entry defining justice. It is the first production of a Greek tragedy I have seen that stages its own programme notes.
And that is a shame, because there are many fine performances here. Robert Bowman, Michael Gould, Sebastian Harcombe and Paul Hilton make a remarkable wheelbound chorus, and as Athene, Joy Richardson brings the evening to its forceful and moving conclusion, ending the cycle of violence and urging the Furies to put revenge behind them and resolve their differences through the state. "There is no hope nor future," says the chorus, "For a land/ Whose mind is split/ Into two, and where each half/ Strives only to destroy the other." In the light of last week's events in Northern Ireland, Aeschylus's trilogy needed no gimmicks to resonate loud and clear.
'The Oresteia': RNT Cottesloe, SE1 (0171 452 3000)
Swan, Stratford (01789 403403) to 18 March
Antony Sher stars in Gregory Doran's thrilling production.
New Ambassadors, WC2 (0171 836 6111) to 24 Dec
Polly Teale's astute and transfixing production for Shared Experience.
SEVEN BRIDES FOR SEVEN BROTHERS
BAC, SW11 (0171 223 2223) to 15 Jan
The irrepressible Phil Willmott turns to pistol-packin' cowboys and cowgirls.
OPENING THIS WEEK
RNT Lyttelton, SE1 (0171 452 3000) now previewing, opens Thursday
A story about the Royal Family: Howard Davies directs Zoe Wanamaker and Simon Russell Beale in a new play by Nick Stafford about Queen Caroline.
THE LADY IN THE VAN
Queens, W1 (0171 494 5040) now previewing, opens Tuesday Nicholas Hytner directs Maggie Smith in a new Alan Bennett play where two other actors play the author himself. RB