Theatre / A Satire of the Four Estaites International Conference Centre

Ane Satyre of the Thrie Estaites, Sir David Lyndsay's morality play first performed in 1552, is one of the great landmarks of Scottish culture, and Tyrone Guthrie's 1948 revival is one of the landmarks of the Edinburgh Festival. Given this history, you can see exactly why updating the play must have seemed an attractive way of marking the 50th festival; it's harder to see how John McGrath's ragbag of truisms and whinges, wrapped up in plodding doggerel, works as a tribute to anybody.

So long as the allegory remains reasonably abstract, it's easy to go along with: McGrath, you learn, is in favour of Love and Respect, Charity, Democracy and Equality, who all appear as characters in the play. He likes Humanity, the dethroned king who must be married to pretty Jenny McReddie if the New Scotland, of which she is the personification, is to be worth anything. What he doesn't like is the Fourth Estate, represented here by Lord Merde, a repellent Australian media magnate, and his hangers- on.

All this is reasonable; but as soon as the play descends into particularities, it's as if a drunk has barged into an argument on your side, making your own position seem embarrassingly crude. Merde's chief act of evil, for instance, is to bribe Page 3 girl Gloria Cupsize into seducing Humanity. Never mind that Page 3 disappeared some time ago; this was never an adequate characterisation of what's wrong with the multinational media conglomerates. We get a lot of xenophobic swipes at stupidity and cant south of the border, and at coarse Australian greed. McGrath talks in the programme about how Scotland has to grow up: shoving the blame for all the nation's ills onto English politicians and foreign-owned media doesn't sound like a very good start.

The overall effect is to push you towards sympathising with McGrath's targets - especially Sir Righteous Denunciation, a Times columnist and former bigwig at the BBC and the Arts Council, with a sideline in antiquarian books, portrayed here as a tippling crypto-fascist with a grudge against "arty farties and woofters". Surely, you think, he isn't this bad?

There are some neat jokes (Lord Merde wears a pair of Skippy the Bush Kangaroo slippers - "to remind my employees that no one is indispensable"), some jolly interludes with the Mary Erskine School Highland Dancers, and some effective rabble-rousing by Sylvester McCoy. Amy Trompetter, the designer, does a nice line in Steadmanesque caricature, too. Overall, though, a disappointingly blunt instrument.

To 28 August

ROBERT HANKS