"I am a touchstone," says 69-year-old tenor Peter Pears modestly. "It is not, obviously, for my golden voice -- but critics on the whole have kept on coming back to my recordings when a new one comes out. It's gratifying."

At twice the age when most tenor voices begin to fade, Pears is still using his -- although more sparingly now -- with the kind of intelligence that promotes longevity. His was never a sensuous voice, but he was and is unique among tenors in the shaping of a musical phrase, the shading of a word.

And he has been fortunate in having his music tailor-made for him. As one poet wrote: Peter Pears Never gives himself airs. He gets them all written By Benjamin Britten.

Whoever wrote the verse has neatly summarized one of the most remarkable partnerships in the history of music. Britten and Pears lived together for more than 40 years -- during which the most notable British composer of the century served as the tenor's piano accompanist and composer in residence.

Now, three years after Britten's death, Pears is not only the touchstone for the interpretation of Britten's music but in a sense, the keeper of the sacred flame.

Britten first met Pears in 1936, when he helped Pears "tidy up" papers and personal effects after the death of a mutual friend. Now, Pears is going through the same process again, rereading old letters from Britten that date back to the '30s and musing that "I really must write a book about Ben."

It is not strictlly true, as the poem says (Pears believes the author to be the BBC's John Amis, heard here Sundays on WETA-FM), that "all" of Pears' music was composed by Britten. Witold Lutoslawski and Michael Tippett are among the others who have composed for him, and he has made unique recordings of Bach and Schubert, among others.

But the Britten-Pears collaboration has enriched the tenor repertoire not only with the title operatic roles of "Peter Grimes" and "Albert Herring," but with central roles in such operas as "A Turn of the Screw" and "Billy Budd" as well as such notable song cycles as the "Serenade for Tenor, Horn and Strings" and the haunting "Nocturne," which Pears sang last night as part of a varied program at the Library of Congress.

"I can't help feeling a bit proprietary about Ben's music," says Pears, who has gradually phased out some parts of his Britten repertoire that are becoming difficult, and now hears other tenors singing "his" music.

"What I miss most in other tenors," he says, "is the feeling for the text. Most of them have better voices than I have, but the thing that most interested Ben was re-creating the poetry." He is now teaching other tenors in a nine-week summer program and occasional weekend sessions at Snape, England, near the site of the Aldeburgh Festival, which he and Britten founded in 1948 so that they could perform their music close to home.

"We work hard there," says Pears, "harder, in my experience, than the singers do at institutes in London. We work primarily on interpretation -- I hope that they are already more or less in command of their voices when they come to me.

"I've worked with some marvelous singers, including some from Washington whom I am meeting again on this visit. There are three young Washington tenors whom I find particularly promising: Douglas Robinson, Stanley Cornett and James McDonald. It was a pleasure working with them."

"One has one's voice," Pears says, "and one can do certain things about it, but one can't really alter it.When another tenor sings this music, there is always a lot of him in what he does. And sometimes the singer's vocal personality just doesn't go with Ben's music."

When Pears refers to Britten as "the world's greatest piano accompanist," he is not offering his own opinion but that of Gerald Moore -- to whom everyone else gives that title. Pears is now being accompanied occasionally by Murray Perahia, who is very good, he says. "I am lucky to have him -- he has a brilliant solo career of his own -- but it's difficult to accept any pianist after Ben."

The secret of Britten's accompaniments, Pears believes, is that "he was a marvelous pianist but not interested in the piano as such. He used to get impatient with it and try to make it sound like a clarinet, for example. And because he was not in love with the instrument, he didn't want to make it sound all the time, as other pianists do. He believed in silence.'

At an age when most tenors have long since lapsed into silence, Pears is beginning to look at retirement, and his feelings are ambivalent. "I have decided not to sing Bach's 'St. Matthew Passion' any more," he says, referring to the most demanding music in the standard tenor repertoire -- music that, by general critical consensus, he has sung more perfectly than any other.

"I had a collapse last year," he says, almost casually. "At first I thought it was a stroke, but it wasn't -- it was exhaustion. It took me a long time to regain my strength and longer to regain my confidence."

The confidence seems still slightly shaky. "I hope tonight will be all right," he says with several variations in the course of an hour-long conversation.

"I have been singing for 45 years, and that's long enough. I have a right to retire . . . but I enjoy it so much."