John Shirley-Quirk, one of the most admired operatic bass-baritones of the 20th century and a self-described “torchbearer” for his countryman, the English composer Benjamin Britten, died April 7 in a village near Bath. He was 82.

His death was announced by the Peabody Institute in Baltimore, where Mr. Shirley-Quirk taught for two decades. The cause was cancer, said his wife, Terry Shirley-Quirk.

John Shirley-Quirk died April 7. (Metropolitan Opera Archives)

Working in a time-honored and brutally challenging art form, many opera singers begin their classical training at young ages and from then on pursue their musical careers with single-minded purpose. Many also never meet the creators of the works they bring to life on stage, the composers having died years or even centuries earlier.

Mr. Shirley-Quirk was exceptional on both counts. He began his professional life as a science teacher and devoted himself full time to singing, which he had loved since his boyhood and initially developed as a side activity, in his 30s. Almost immediately, he caught the attention of Britten, who was recognized by the time of his death in 1976 as a titan of operatic composition.

In the early 1960s, Mr. Shirley-Quirk recalled, Britten happened to hear him sing in a performance of Bach’s “Christmas Oratorio.” The composer approached Mr. Shirley-Quirk after the concert and expressed appreciation of his talent. Not long after, Mr. Shirley-Quirk was cast as the ferryman in “Curlew River” (1964), one of Britten’s church parables.

Mr. Shirley-Quirk became a prominent member of the English Opera Group, a company formed by Britten and others, and helped define roles in Britten operas including “The Burning Fiery Furnace” (1966) and “The Prodigal Son” (1968), also church parables. He said he had the “greatest affinity” for his role as Spencer Coyle in Britten’s “Owen Wingrave” (1970), an opera inspired by a work by Henry James.

In “Death in Venice” (1973), an adaptation of Thomas Mann’s novella and Britten’s final opera, Mr. Shirley-Quirk took on no fewer than seven parts: the traveler, the elderly fop, the old gondolier, the hotel manager, the hotel barber, the leader of the players and the voice of Dionysus. He made his debut at New York’s Metropolitan Opera in 1974 in all of those roles.

Mr. Shirley-Quirk sang in other leading venues around the world, including the Royal Opera House at London’s Covent Garden, the Sydney Opera House in Australia and Milan’s La Scala. He sang in German in works by Mozart and Richard Strauss and in Russian performing the music of Modest Mussorgsky. But he took particular pride in singing, and singing properly, in his native language.

“No one would dream of going on stage and speaking Shakespeare without studying how to speak English,” he once told the Los Angeles Times. “But there are English singers who go on stage and perpetrate all sorts of monstrosities. They have a British passport. But that’s not good enough, really. It’s a subject — a language, a technique — that has to be studied.”

He did not realize until age 40, he said, that he would have a “remarkable career.”

John Stanton Shirley-Quirk was born Aug. 28, 1931, in Liverpool. (“Quirk” was his family name in Manx, a Celtic language used on the Isle of Man, while “Shirley” referred to the village in Derbyshire where his ancestors lived, according to various accounts.)

He said he had no musical training before he joined a church choir at 9. “My voice changed over the years — from soprano to alto and finally to bass-baritone,” he told an interviewer with the Frome Festival in England, “but I would have been singing wherever it ‘landed.’ ”

During World War II, he said, he was evacuated to North Wales and “lost a year” of his education because of wartime chaos. In addition to his choral work, his early musical preparation included violin lessons, for which he said his parents paid a shilling per five minutes.

“They used to last much longer, of course,” he recalled. At 13, he received a music scholarship that eased his family’s financial burden.

He studied physical chemistry at the University of Liverpool and worked briefly in industrial chemistry before teaching physics in the Royal Air Force. While studying music in London with the baritone Roy Henderson, Mr. Shirley-Quirk said, he decided that he had to choose between science and music. He went with the latter and quickly found success.

“The artist has just about everything going for him,” music critic Raymond Ericson wrote in the New York Times in 1968. “Power, range, the long-spun phrases were all there.”

During his years at the Peabody conservatory, Mr. Shirley-Quirk lived in Maryland, in Clarksville and Baltimore. He was inspired to take dual citizenship after the terrorist attacks of Sept. 11, 2001.

Mr. Shirley-Quirk was preceded in death by his first wife, the former Patricia Hastie. His second wife, the former Sara Watkins, died in 1997. Their daughter Emily Shirley-Quirk died in 2001.

Survivors include his wife of five years, the former Terry Cardoza, of Avoncliff, England; two children from his first marriage, Kate Shirley-Quirk of Pangbourne, England, and Peter Shirley-Quirk of Tilehurst, England; two children from his second marriage, Benjamin Shirley-Quirk of Hereford, England, and Julia Shirley-Quirk of Bristol, England; a stepdaughter, Sara Perez of San Diego; and four grandchildren.

Mr. Shirley-Quirk’s extensive recordings included the works of Britten — his interpretation of the “War Requiem” was regarded as a classic — and other modern composers. He also recorded the much older music of Bach and Handel. In the Frome Festival interview, he reflected on the challenge of interpreting the written notations of a composer, living or dead.

“That is the delight of being a performer — trying to understand the composers,” he said. “If you hear a sentence on the phone you are missing the body language. The piece of music is just a telephoned message, really. For me the body language is missing. As a performer it is your job to find it. This is the constant search for meaning.”