GREAT BRITAIN'S "other" ballet company - not the lordly Royal Ballet, but the lively, smaller troupe known as the London Festival Ballet - makes its Kennedy Center debut Tuesday night with Rudolf Nureyev heading the list of notable dance artists.

On the strength of Nureyev's appearance, the two-week engagement is virtually sold out. Of all ballet's superstars, Nureyev is the most generous with audiences - no matter which program you may have chosen to attend, you can be sure of seeing him dance. As he did in the company's just concluded New York run at the Metropolitan Opera House, Nureyev will appear at every performance.

Opening night, moreover, as well as the entire first week of performances, will be given over to Nureyev's own new production of "Romeo and Juliet" with the familiar Prokofiev score. Nureyev himself will portray Romeo each time, partnering three different Juliets among the company's ballerinas - Eva Evdokimova, Patricia Ruanne and Elisabetta Terabust.

During the second week he'll be seen as Count Albrecht in Mary Skeaping's production of "Giselle," with Evdokimova and Terabust alternating in the title role. In the mixed repertory program, he'll also be seen in two Fokine ballets, "Scheherazade" and "LeSpectre de la Rose" - in roles made famous by Nijinsky - as well as in the Bournonville "Conservatoire."

The only ballet in which he won't appear will be Ronald Hynd's "The Sanguine Fan," commissioned by Princess Grace of Monaco for Monte Carlo's International Arts Festival in 1976.

This is the second time the London Festival Ballet has visited this country, but it's the troupe's first appearance on this side of the Atlantic since the company was reorganized in 1968 under its current artistic director, former Royal Ballet ballerina Beryl Grey.

In her 10-year stewardship she's imparted a distinctive stamp of her own to the company's repertoire, its dancers, its style. It was Grey who enlisted Nureyev as a guest artist and invited him to mount two productions of his own - "Sleeping Beauty" in 1975 and "Romeo and Juliet" last year - for the company. It was she too who got Mary Skeaping to redo "Giselle" for the LFB, and she who has enlisted such guest artists, besides Nureyev, as Natalia Makarova, Lynn Seymour, Elisabetta Terabust of the Rome Opera and Patrice Bart of the Paris Opera.

At 51, Grey is tall, slender and spry, with a ballerina's gait and grace very much intact, and a disarming, dimpled smile that seems to accentuate even further the English look of her features. At an interview at the Kennedy Center a few weeks ago she peered admiringly around the center's press lounge and observed, "We don't have press rooms in London, you know." Asked where the London dance critics congregate during intermissions, she replied, "Well, they usually go to the bar - that's probably the secret of their elegant British prose."

As a dancer, Grey holds something of a legendary place in British ballet annals, having been one of the first native-born dancers to gain a truly international reputation. And her career began at such an early age that she's still remembered as England's first "baby ballerina."

London-born and London-trained (Ninette de Valois and Vera Volkova were among the teachers), she joined the Sadler's Wells (later the Royal) Ballet as its youngest member in 1941 she was 14. By the following year, she was already dancing major roles, and on her 15th birthday she became the youngest dancer ever to undertake the taxing dual lead of Odette-Odile in "Swan Lake."

Elsewhere she has recalled that as a child she used to dream that "Margot Fonteyn would get ill and I would get to do the Princess," and that's precisely what happened. The title roles in "Giselle" and "Sleeping Beauty" followed not long afterward, and in short order Grey evolved into one of the company's main classical stars.

She left the Royal in 1957 to be free to accept outside, freelance engagements, but returned to the company frequently as a guest artist. In 1964, she became the first Western ballerina to dance with the Bolshoi Ballet in Moscow. Her experience with the Bolshoi and other Soviet troupes, and her travels in China, where she appeared with the Peking Ballet, led to the writing of two books: "Red Curtain Up" in 1958 and "Through the Bamboo Curtain" in 1965.

When, at a critical juncture in the history of the London Festival Ballet, she was invited in 1967 to assist in the mounting of a new production of "Sleeping Beauty," it was the start of an association that became the center of her working life, with her appointment as the company's first woman director the following year.

She recalls the crisis, one among many in the company's earlier years, that brought about the reorganization and her own appointment. "By 1967, the company was pretty well bankrupt as a private institution," she says. "Julian Braunsweg, who managed the company in those days, had wanted to mount a very expensive new production of 'Swan Lake.' But unfortunately, they premiered it at a theater way off the beaten track, where there was no tourist trade at all, and it was a financial disaster - they didn't get the take to cover anywhere near all the bills."

It was, in effect, government subsidy that saved the day. Until 1962 the company had had no government support, but under Grey's new regime, generous grants were received from both the British Arts Council and the Greater London Council, and since then this help has steadily increased, along with private and industrial patronage.

Even so, making ends meet is still no easy matter. "Even with our grants," Grey says, "we will have to earn 64 percent of our budget from box-office receipts. With inflation riding so high, and given the country's economic troubles of the past three or four years, the grants simply haven't kept pace with our increasing costs. So we work very hard for our keep. The dancers are on yearly contracts that allow them four weeks holiday, and we now give some 280 performances a year. In addition to 15 weeks in London, we tour England, Wales and Scotland for 14 or 15 weeks, and spend a couple of months abroad as well."

Recent help has come from television. "The Royal Ballet has had this ever-renewing contract to do two or three ballets a year on BBC," Grey says, "but we had our first big break with TV last Christmas with Ronald Hynd's new production of 'Nutcracker.'

"The Hynd production extends the traditional staging and brings it a little nearer the original story. Clara's still a child, but while she goes on eating her sweets and playing with dolls, Hynd has given her an elder sister who gets to dance with the Prince. And he's brought back Drosselmeyer's nephew, as a nasty sort of fellow who later becomes the Mouse King in the battle scene. We had our diehards, of course, as usual, crying, 'Oh, why did you change it,' but it's really a very charming version."

Grey waxes enthusiastic over the Kennedy Center repertory as well. "Nureyev's 'Romeo and Juliet' is a completely new conception, much closer to Shakespeare's text than earlier versions - much more rough, crude and realistic. Ezio Frigerio's sets are extraordinary, the most beautiful backcloths I've ever seen in a theater. Rudi wanted a feeling of oppression, so there are enormous sliding walls and huge pillars.

"Rudi also makes a great point at the start of the action of Rosalind's indifference to Romeo, so that it's clear he falls in love with Juliet on the rebound. And Juliet is portrayed as ripe for her first love - she can't wait to get in bed with Romeo. The fight scenes are especially exciting and very authentic in feeling, too. We found in London that the straight theater crowd was going big for this production, and it was tremendous box-office for us - five weeks sold out in London, and in Paris we were getting 6,000 a night."

Special interest attaches to the score of Hynd's "The Sanguine Fan," which is by Sir Edward Elgar. "It was the only ballet Elgar ever wrote, you see," Grey says, "and it never really had a professional stage performance - the music was rediscovered recently, and recorded, by Adrian Boult. Ronny Hynd scrapped the original story - he said he just couldn't get anywhere with it as a ballet - and gave it an English, turn-of-the-century setting - it's sort of rather like 'Lady Windemere's Fan' with a bit of Anouilh's romantic irony thrown in."

Something that has remained a constant for the London Festival Ballet through all the vicissitudes since its founding in 1950 by Alicia Markova and Anton Dolin is a fondness for the ballet "classics" and a sense of mision about keeping them fresh for succeeding generations.

There's evidence of this in the Kennedy Center repertoire not only in Bournonville's "Conservatoire" and Mary Skeaping's "Giselle" (which attempts to restore more of the spirit and detail of the original Paris production of 1841), but also in the two Fokine ballets from the early days of the Diaghilev Ballets Russes - "Le Spectre de la Rose" and "Scheherazade." Grey seems a bit worried about the effect of the latter here: "In England," she says, "they just lap it up - I just hope American audiences won't find it too old-fashioned."

One thing that may help is the reproducion, by artist Geoffrey Guy, of Leon Bakst's voluptuous set and costume designs for the Diaghilev company, a tough of visual exoticism that could exert a considerable spell on its own - not that rudolf Nureyev should need any assistance.