Dr Williamson told the Independent that more disreputable facts were emerging about Britten - notably that he spent the war in the US "to escape", while other composers, such as Sir Michael Tippett, stayed in Britain and went to jail as conscientious objectors.
Speaking of Britten's reputation yesterday he said: "There is a backlash. People are coming out... and suddenly getting the courage to speak."
Dr Williamson's views have shocked the Britten-Pears Foundation, which was set up to run Britten's estate after his death, and co-named after Britten's lifelong partner Peter Pears. Four years ago it had to contend with Humphrey Carpenter's 1992 biography which looked at Britten's homosexuality and friendships with boys. Donald Mitchell, the composer's editor at Faber & Faber, and one of the trustees, said that Dr Williamson's description of Britten's music as ephemeral was "eccentric".
"It is scarcely borne out by the ever-increasing worldwide reception and performance of his works," he said. "It is simply untrue to state that Britten 'spent the war in America to escape'. That overlooks that he returned to this country at the height of the war, in March 1942, fully aware that he would face a tribunal as a conscientious objector. He would have returned yet earlier if he had secured a passage." Mr Mitchell's defence of Britten's abilities was backed by Alexander Goehr, Professor of Music at Cambridge University and a composer himself. "It would be better if there weren't any biographies of composers... and it would be better if we assessed them on the basis of their work," he said. "It seems to me that Britten's reputation is rising if anything, because in his lifetime people like myself were put off by his trafficking with nobility and the feeling of his being a slightly official composer.
"Now that we can see his whole career I can't claim to admire every single piece, but on the other hand there are a considerable number of works which have grown in stature... and some are masterpieces."
Stephen Walsh, co-editor of the Viking Opera Guide, said it was obvious that Britten was an outstanding composer, with works performed widely. "I don't think he is the greatest composer of the 20th century myself. A lot of disagreeable facts about Britten have come out, but none of this seems to me relevant to the question of whether his music will last."Reuse content