But in what sense is the public watching 'Jonathan Miller's Rigoletto' when the director himself hasn't been near it in years? The answer is to be found in The Book, an interleaved copy of the vocal score in which the director's assistant has assiduously recorded every aspect of the new show, bar by bar, blow by blow, to create a blueprint for later revivals. The more the book succeeds in capturing the fleeting moods of the original concept - and not just the mechanical aspects of entrances, exits and bits of business - the more faithful a revival can be to the spirit and not simply the letter of the original.
David Ritch, who acted as Miller's assistant on the 1979 premiere and will be reviving it in January, brings out the book for Britten's The Turn of the Screw (after Henry James's supernatural novella). Between its covers is his record of every stage the production has gone through in the meantime, with reduced scale groundplans of the set, the occasional freehand drawing and detailed descriptions of every on-stage happening, each remark cross-referenced to a corresponding point in the score.
Ritch turns to a page at random: 'At this particular moment on page 32, during Variation 3, on the first bar of the fifth stave, at Figure 21, you know that Mrs Grose and the Governess start walking together upstage towards upstage left. The Governess continues walking upstage, towards upstage centre, having departed from Mrs Grose, who makes her exit, downstage left; at the precise same moment, a servant enters from downstage right, moves up towards the centre and, at a given point (he turns to p 33), meets the Governess upstage centre. And there is the specific chord on which we decided it would be a good atmospheric moment for them to meet.'
The secret of 'doing it by the book', though, is to remain loyal to the spirit of the original concept without reducing it to routine. There's a story about the great Russian bass Chaliapin, the Boris Godunov of the century, letting one of his pupils stand in for him at a rehearsal and asking afterwards why, at a certain point, the younger man had suddenly disappeared upstage. 'But, master,' the pupil replied, 'you always do that.' 'Ah,' replied the singer, 'but I do it to have a spit.'
So moves alone may be misleading: more important are the motivations. Ritch finds another page - where the Governess, en route to her new charges, worries about how Mrs Grose, the housekeeper, will receive her. 'How will she welcome me?' she sings, and the word 'she' is ringed in Ritch's copy and cross-referenced to the word 'concern' on the opposite page. It's a reminder to get the soprano to ask herself some basic questions: Will she be jealous? Will she resent losing control of the children? 'This is the Governess's 'To be or not to be',' Ritch observes. 'No actor would dream of going into such a monologue without making that sort of enquiry.'
Inevitably cast changes bring subtle realignments in relationships and reassessments of emphasis. 'I personally enjoy the challenge of all three situations,' says Ritch: 'where you get the same cast back and you have to revitalise it; where you get one crucial new member who causes the rest of the cast to rethink; and then I love being given a completely new cast in a production I've really got my fingers on.'
Casts may come and casts may go, but as long as the book is kept up to date, the concept can be handed down from generation to generation. Ritch's assistant on the August Rigoletto will himself direct it in March, while his assistant on next year's Screw will in turn direct the show in Canada after that. 'I can't do it,' says Ritch, 'so I shall train him in it when we do the revival here and then I will say: There you are, there's the bible, do what you can and for God's sake don't lose it]'
Books do get lost, however, and so do other things - bits of set, continuity of tradition, even faith in the concept. When that happens, it's probably time to do a new production. There is, however, one alternative: so long as the sets and costumes survive, a company can always do a 're-staging' by inviting a new director to devise a fresh production within existing designs.
When Stephen Medcalf was booked to do Le nozze di Figaro for the current Glyndebourne tour, it was meant to be a 're-staging' using the existing designs from Sir Peter Hall's 1989 festival staging. But then the sets got burnt in a storeroom fire and John Gunter asked for the opportunity to rethink his original designs. The costumes, however, had survived the flames and the decision to retain them basically defined Medcalf's approach: 'Because they are clearly naturalistic and in period, so we couldn't have too much abstraction in the staging.' Medcalf hopes he has injected many changes of emphasis: 'The sets are much more simple and uncluttered; I've added a stronger political edge; and I've tried to make the last act, in particular, much more expressionistic, much harsher.' Yet dress sense alone was enough to make this a 'straight' rather than a 'concept' Figaro.
In a sense Elijah Moshinsky was luckier when he was asked, back in 1975, to revive a 1950s Covent Garden staging of Britten's Peter Grimes: the entire production, it turned out, had disintegrated in the warehouse and Moshinsky managed to convince the management that it would be cheaper to let him do a brand new show than to rebuild the old one. The stark Brechtian style of the result made the young director's name. Yet Moshinsky is no friend of change for change's sake, condemning the current 'fetish for innovation' that makes audiences demand a new concept from every new production. 'There are limited amounts you can do to an opera before pulling it out of shape altogether just to make it look different from the previous version.' If a production really succeeds in cutting to the heart of a piece, Moshinsky can see no reason why it shouldn't run for ever.
With recent Royal Opera House stagings of Macbeth, Otello, Attila and Boccanegra beneath his belt (plus Stiffelio to come), Moshinsky appears set on an unofficial Covent Garden Verdi cycle. Yet, at risk of doing himself out of a job, he trusts the house has no plans to replace the classic 1958 Visconti Don Carlos. 'I can't see why you would want to replace it. It's a design classic, like the Coca-Cola bottle. The thing that Visconti brought to it was a kind of still grandeur that we've rather lost today: those particular settings impose a kind of noble form of acting that only an Italian aristocrat could understand.'
Medcalf's Le nozze di Figaro for GTO is at Sadler's Wells EC1 (071-278 8916) 10, 14, 20, 23 Oct and on tour; Moshinsky's Otello opens at the ROH on 23 OctReuse content