Can everybody hear me?

`Antony and Cleopatra' fell foul of the National Theatre's acoustics. Now Trevor Nunn is ready to make a noise with `Troilus and Cressida'. He talks to Stephen Fay

On the concrete wall of Trevor Nunn's office at the National Theatre are 44 black and white portraits. There are no stars and only a few familiar faces: Michael Bryant, Simon Russell Beale, Denis Quilley. There are a few actors you recognise without immediately being able to put a name to them. Men outnumber women, and there is sprinkling of black faces.

This is Nunn's new company of actors, an ensemble that is his first real gamble since he took over at the NT almost 18 months ago. They will perform six plays, the first of which - Shakespeare's Troilus and Cressida - begins previews this week. It is to be followed a month later by Leonard Bernstein's musical version of Voltaire's Candide.

All the theatrical purists and historians hold that ensemble work is what the NT is for. It is what Nunn cut his teeth on in Stratford-upon- Avon. The mixture of tragedy and comedy, verse and song, perfectly fits his dual nature - part showman, part puritan. But just because he is good at it doesn't minimise the risk. All the recently received wisdom about the London theatre suggests that it is driven by market forces, and needs stars like Kevin Spacey and Nicole Kidman, even though they will stay only for short runs. By bucking the trend, Nunn may be betting the store.

NUNN RETURNS to his office from a Troilus rehearsal shortly after 8.30pm. He consumes half a sandwich and takes the first sips from a glass of white of white wine before letting loose a torrent of talk. He has been rehearsing for 10 hours, but directors of the NT have to take long days for granted: the evening rehearsal is to make up for time Nunn has lost supervising the transfer of his successful NT production of Oklahoma! to the Lyceum in the West End, and in flying to and from New York where a Tennessee Williams play he has directed - Not About Nightingales - opened last week.

When Nunn ran the Royal Shakespeare Company in the Sixties and Seventies a colleague said that he looked like every Vietnamese waiter in the world. Though he is 59 now, you can still see what he meant: it is the shock of black hair without a trace of grey, the trimmed beard, the bags under the eyes, the otherwise unlined face. The difference between then and now is that Nunn has become a man of substance, physically as well as materially. He dresses simply in a blue shirt and jeans, but his tummy falls over his brown belt. He says that after losing three-and-a-half stone, he has put one and a half back on. He must have been enormous.

There really are two Nunns. The showman has made his fortune, wildly estimated at pounds 35m, from directing modern musicals like Les Miserables, Cats and Sunset Boulevard. This Nunn speaks the extravagant language of an impresario: introducing an ensemble at the NT compares "fairly precisely with turning round a supertanker in the Thames estuary". He contemplates it "with a mixture of humility, fear and nerve-tingling excitement".

The puritanical Nunn modestly points out that there is nothing new in what he is doing. The NT began as a permanent ensemble formed around Laurence Olivier's legend; Sir Peter Hall ingeniously found a way of continuing ensemble work in the three theatres on the South Bank. Sir Richard Eyre was the exception: "He wanted a new-play policy, and if a major writer wanted 27 black people and two nuns, he got it," says Nunn.

The showman enthuses about the Millennium year as a time for something special. The puritan embraces the possibility of failure: "If audiences no longer wish to follow the fortunes of a company and must have stars, we'll have to learn that lesson. But I've missed the ensemble principle gravely, and I think the attempt to bring it back at this juncture of the NT's history is an honourable one."

Honourable, certainly, but expensive too.

Directors in the subsidised theatre have been dismayed by Nunn's refusal to join their attacks on the Government's parsimonious attitude towards the theatre, especially in the regions. He believes the right way to get bigger grants is to keep quiet. "In the short run, he has been proved right," says a competitor. Last December the Arts Council announced a much bigger increase for the NT than for any other subsidised theatre - an extra pounds 1m in the next financial year, taking its basic subsidy to pounds 12,167,000 after six years in which the grant remained the same.

For the past few years the NT has stayed in the black only by consuming its modest reserves and ignoring its repertory tradition - charging higher seat prices for long runs of box-office hits like Guys and Dolls, Oklahoma!, Wind in the Willows and Peter Pan. These have proved to be great popular hits, but the breach of tradition has perturbed critics like the Guardian's Michael Billington who say long-running musicals are "not what the National Theatre is for".

Good houses for Oklahoma! and Peter Pan have enabled the NT to stay within budget so far this financial year, and the transfer of shows to the West End (three are running there currently) and to New York (there will be three transfers there by the spring) boosts its income. But Jenny McIntosh, the NT's executive director, reports that this extra money "is not enough to develop a cushion".

McIntosh adds that the pounds 1m boost represents about half the value of what they had lost through inflation during six years of standstill grants, so Nunn is initiating his ensemble at a time when the NT is financially insecure. He gets some extra sponsorship money from an anonymous American donor who lives in London, but his first two shows are in the Olivier Theatre, which is never cheap. If shows there don't do good business, the haemorrhage of cash can be frightening.

Nunn has before him the spectre of Antony and Cleopatra. When it opened last autumn with Helen Mirren and Alan Rickman in the leading roles, the run was sold out before the first night, which then turned into one of the great critical disasters in the NT's history, with Rickman's acting and Sean Mathias's direction attracting special derision from the critics. Nunn himself was criticised for asking Mathias, who had never directed a Shakespeare play before, to direct one of the most difficult plays in the cannon in a forbidding theatre. The gossip is that he did so because other directors has turned the job down

"It's entirely true that it is immensely difficult to get directors to work in the Olivier because of the extreme problem of the acoustics," he replies. Musicals work there because all the performers are miked and audible through the sound system. "I'm very used to people saying `I'd love to do it, but if it's in the Olivier, I'd rather not'. I've already done two-and-a-half shows in the Olivier, but I've got to put my money where my mouth is. I've got to lead from the front." The truth is that the Olivier sorts the men from the boys.

The lingering effect of the failure of Antony and Cleopatra is on the box office. At the moment when Nunn's ensemble needs maximum encouragement the audience seems to be waiting for the reviews before spending its money. Nunn's wager, which puts the NT's financial stability at risk to achieve his artistic ambitions, begins to look heroic.

IT IS 17 years since Nunn directed a Shakespeare play on a large stage, and he had become a virtual stranger to large-scale work some years before that. The work in small spaces was often brilliant (his 1976 Macbeth at the Old Vic is the best single Shakespeare production I have seen ), and he reverts to a small scale when he directs The Merchant of Venice at the Cottesloe in June. But now he is working in the wide open spaces of the Olivier, with a new stage thrust into the auditorium, designed to increase the actors' presence and improve the sound.

And, after a decade of big musicals, does he still love Shakespeare? "Emphatically," he says. "I think it's a 20th-century habit of mind to say that either you're a classicist or you're a populist. I don't enjoy that sort of specialisation." Last year Nunn chaired a forum at the NT on Shakespearean verse speaking, and realised how much he had missed it. When rehearsals for Troilus began he told the company they could forget the text for a week because they were going to have a Shakespeare workshop; he found it "exhilarating".

He got John Barton, his old tutor from Stratford, to talk about verse; that was "magical". Nunn is pragmatic about verse speaking. "I think that Shakespeare's style changed so repeatedly that one set of rules absolutely will not do. If it's a choice between structure and music on one hand and meaning on the other, I'm with the meaning."

In the absence of a cast of stars, Nunn is falling back on a theme that became familiar with the RSC at Stratford: "Shakespeare is the star; the work is the star; the company is the star," he says. But many members of that company became stars, like Judi Dench and Diana Rigg. If Nunn's ensemble works, some of those faces on his wall ought to become stars themselves. If, however, the company's fire is unlit and they do remain anonymous, Trevor Nunn's problems will be more about money than art.

`Troilus and Cressida': Olivier Theatre, SE1 (0171-452 3000); previews from 6 March; opens 15 March.