The shabby rehearsal studio of the company's premises in Baron's Court, west London, is as hot as a hospital in a heatwave. Soloists and principals slouch around in sweat-soaked tracksuit bottoms, looking like refugees from a rave. Beneath the beautiful surface of a new Royal Ballet production lies a chipped and grimy world of torn leotards, frayed tempers and bags under the eyes. Everyone looks younger off stage - and thinner. Girls who seem almost hefty in performance are revealed as waif-like. They make me wish I'd brought food parcels. The men look a lot better in the flesh: butcher and much bigger; the addition of a little sweat and stubble is a definite improvement on their lacquered on-stage perfection.
Since the end of February, Viviana Durante and the rest of the company have been rehearsing a version of Don Quixote acquired from Mikhail Baryshnikov, who created it for the American Ballet Theatre in 1978. They work under the beady eye of Susan Jones, a freelance ballet fixer nominated by Baryshnikov to recreate his work. Small and decidedly plump, she enthuses wildly about the range of starry international dancers who will be performing this Spanish extravaganza and feels we will be seeing a new side of them. 'Stylistically this ballet - the whole peppery flavour of it - is something they just haven't done before,' she says.
The men's class that morning had been traumatised by the arrival of a small group of Japanese visitors taking photographs. The boys are used to 24 hours' notice of a photographer's presence, and the notoriously camera- shy French superstar Sylvie Guillem must be faxed at home.
Ms Guillem herself lopes by in Michelin-man quilted trousers, held up with braces. She sits on the floor alone eating crisps (ready salted). She is not at all happy with the space available for rehearsal. There are too many people in the studio, apparently, with such stars as Darcey Bussell, Zoltan Solymosi, Viviana Durante, Irek Mukhamedov and Tetsuya Kumakawa all jostling for room.
Fiona Chadwick bursts across the stage in a crisp series of jumps and an impressively Hispanic turn of the head. 'It looks good, Fi,' enthuses a colleague. But the dancer pulls a face and hobbles to the side of the room clutching her back: 'I feel like I've done three acts.'
This is the wrong side of the fabric: untidy, unfinished, painful. The smiles come later, but they will be as carefully choreographed and artificial as the pointe work. Someone enters with the contents of a bizarre shopping list: two bags of tambourines, a basket of red and green peppers and a large creel of plaster fish.
It's a simple plot, only loosely based on Cervantes's novel: Basilio the barber wants to marry Kitri, whose father has other plans; Basilio marries Kitri. The mad old Don and Sancho Panza wander in and out of the action, providing comedy, pathos and the odd windmill. But the ballet is crawling with props: swords, lances, tambourines, fans. The fans are crucial to the Spanish look, and everyone is practising like mad. One of the company's native Spaniards flicks her fan open with a sparkle and panache bred in the bone - and drops it. All the fans are falling to bits, but it's hoped that the new ones from Spain will withstand the treatment.
More intensive rehearsals take place in one of the smaller studios. Donald MacLeary, Royal Ballet star of the Sixties and Seventies, conducts a pas de deux rehearsal with Viviana Durante and the former Bolshoi beefcake Irek Mukhamedov - one of the seven different partnerships scheduled to dance the ballet.
They are trying to work out a compromise that will satisfy Baryshnikov's watchdog but still be comfortable for the dancers. There are mutinous mutterings. 'She wants it like this. She says it's more Spanish.' Ms Durante despairs: 'We'll have to have signs on the stage.' Her low spirits are understandable. Despite a bad cold, she had performed the gruelling role of Aurora in The Sleeping Beauty within the last 36 hours. 'My temperature went right up.' She has had little chance for relaxation: a one- hour class, an hour and a half of pas de deux rehearsal, rounded off by half an hour's personal coaching.
'Not shoulders. Shoulders nussing] Yum pum. Yum pum.' Madame Messerer, former Bolshoi ballerina, is guest teacher with the company and is coaching the principal girls. She is 84 years old. I close my eyes and try to imagine my granny in pearls and velvet teaching a 25-year-old how to flirt. I open them and there is Madame doing just that, her wizened beauty creasing into little smiles and frowns as she helps the young ballerina. It will be a lot easier once she's in the full tutu and mantilla.
Don Quixote requires a total of 197 costumes in 110 designs. Wizzy Shawyer, the costume supervisor, and her colleagues inhabit a maze of garrets in Covent Garden with tutus hanging from the ceiling like bordello lampshades. 'Mark (Thompson) hasn't designed for ballet before. He wants them to look like real clothes rather than costumes, and he's fighting the stick-on sequins, twinkly bits of lace. A lot of it is black.'
In theory, the funereal effect will be dispelled by the vivid orange set. The key problem designing and fitting for ballet is that the wearers will not keep still. 'We must accommodate movement,' says Ms Shawyer. 'I have a trick of getting them to lift their arms and lean back as far as possible - usually the most extreme movement they have to do. We've had lots of traumas after the event, when they've made a particularly vigorous move and everything's popped out on stage.'
But that's only the lucky ones. 'Sometimes they have a bit of help in the bosom department. The Kitris have to be quite shapely, to achieve a Spanish look.'
To judge from their measurements, it can't have been easy. Although the ballerinas' sinewy waists don't come much slimmer than the standard beauty queen's 24 inches, the resemblance ends there. Some have barely enough hips to hold up their tights. 'One girl has 28 - weeny hips.'
Everyone has at least two fittings - not always a pleasant experience. 'The new corps de ballet girls are usually OK, but once they reach soloist status . . . sometimes they get very difficult,' says Ms Shawyer.
What about the notoriously picky Sylvie Guillem? 'We consulted her first. Everybody always says, 'We want costumes like Sylvie's, they're so wonderful', so we thought we'd solve all the problems on her and make everybody else's the same. She's been very good. Her advice is constructive: she knows her body well, she knows what works and she's very straightforward about it.'
Fitting is simpler with the male costumes. If anything, they fit rather too well. The breeches are constructed from what appears to be a spin-off of the surgical appliance industry made almost entirely from elastic. 'It's a bit like having your muscles clamped by somebody's hands - some of them love it.'
I broach the delicate subject of hygiene and wish I hadn't. 'I'm trying to give them all a pair of tights and a shirt underneath that will absorb the sweat. Some of them do get a bit high . . . That's why they're a bit reluctant to share other people's. The main matador costume (an astonishing confection of braid and beads) won't be cleaned until the end of the run.'
If then. The huge cost of spring cleaning 197 costumes covered in beads is deferred until the company decides whether the ballet is worth reviving. By Thursday morning Ms Shawyer should know whether to alert the dry cleaners.