Bring on the extras. Clare Bayley on 'Mephisto' and the rise of the epic production

The miniskirt is said to be a sign of affluent times: skimpiness never catches on in times of hardship. Perhaps minimalism is the theatrical equivalent of the miniskirt - the bare stage, sparse-talking aesthetic of Beckett and the influence of Grotowski's Poor Theatre both rose to popularity during the wealthy Sixties. But now, in less prosperous times, we are seeing an explosion of large-scale theatrical extravaganzas with dozens of extras. Stephen Daldry put Equity's nose out of joint by employing non-union extras for The Kitchen. Jude Kelly uses West Yorkshire Playhouse Community Theatre members as extras, and is currently recruiting Hackney residents for the transfer of her Warren Mitchell King Lear. At the Riverside Studios, meanwhile, a young German director, Katrin Magrowitz, is presenting an ambitious production of Klaus Mann's Mephisto with a cast of 40.

The inspiration for this latest crop of epics can be attributed to Peter Stein, and blame can also be laid at his door for the current vogue for record-breaking running-times. His Julius Caesar, which came to the Edinburgh Festival in 1993, was both long and huge: 200 extras and four hours. Stein has said that the sound of feet on stage is the key to evoking the past. Whatever the discomfort caused by his Julius Caesar marathon, it was abundantly compensated for by the thrill of hearing, in the distance, the tramp of 200 pairs of boots running along the metal walkways of the Highland Exhibition Hall and then the sight of the owners of those boots crashing over the stage en masse like a breaking wave.

Seeing a stage crowded with people is aesthetically pleasurable, like looking at a well- stocked fridge, especially since stringent budgeting has accustomed us to rarely seeing more than six characters on stage. Watching it affords a sense of proxy opulence, a vicarious tingle of extravagance. David Fielding's 1993 production of Thomas Bernhard's Elizabeth II at the Gate in London played exquisitely with this conceit. The first half of the play is virtually a monologue delivered by a cantankerous old man. In the final act, dozens of extras playing guests in outlandish garb flooded the stage for a party in honour of the eponymous queen's visit. As the volume of chat rose to a deafening roar, word spread that the queen was passing in the street below. The guests rushed offstage to a balcony, whereupon the set split in two as the balcony collapsed into the street below, leaving the old man in the chilly silence of his solitude. It was a lesson in mortal loneliness made dramatically plain.

The technical management of a huge cast of extras, however, is vexatious and unpredictable. Stein is the expert and is able to employ the greatest classical actors (Gert Voss and Edith Clever) for the main roles, thereby balancing detail and mass movement. But Peter Hall came a cropper with his Julius Caesar. As Michael Billington remarked: "We are confronted by 50 Stratford amateurs who look as if they have been caught up in a parish council election rather than the assassination of a world leader."

Magrowitz clearly suffers from a similar problem. While some of her chorus scenes display a boldness you have to enjoy, the scenes of dialogue fail dismally. The fault must lie with both Magrowitz, who attempts to stylise the exchanges by playing them at half speed, and the relatively inexperienced actors. A woman behind me kept muttering "Get on with it!", and the audience ended up panting for another "big" scene.

Ultimately the frustrations of the narrative scenes undermine the enjoyment of the choreographed ones. Julius Caesar is a "play which patently needs crowds; King Lear, the tragedy of a king and his kingdom, demands bodies upon stage; but can a drama about a young actor selling out to the Nazis in prewar Germany justify such treatment? Once the suspicion arises that the extras are there to window-dress an insubstantial text, even the enjoyment of glamour evaporates, and no amount of extra bodies can bring it back.

n 'Mephisto' is at the Riverside Studios, London W6 (0181-741 2255) to 15 Oct