This British cellist and teacher was part of a dozen musicians that worked together in the Melos Ensemble for 25 years beginning in 1950. The expanded ensemble was dedicated to performing chamber works involving six-or-more players -- material that is often neglected because of the difficulty of maintaining such ensembles. These works include the Schubert and Mendelssohn octets, Beethoven Septet, Ravel Introduction and Allegro, and the Schoenberg Serenades. The latter works were recorded in the late '50s for RCA and are among the real jewels in the treasury chest of Schoenberg interpretations. The Melos Ensemble gained an international reputation for its polished performances, and it became closely associated with the music of Benjamin Britten. Pianist and arranger Viola Tunnard, one of this composer's closest collaborators, was also a member of Melos along with musicians such as founding member Cecil Aronowitz, viola; Gervase de Peyer, clarinet; and Richard Adeney, flute. The group premiered Britten's War Requiem in 1962 and also gave many premieres of new chamber works, including Birtwistle's Tragoedia and Maxwell Davies' Seven In Nomine, both in 1965. In 1951, Weil and his associate Aronowitz performed the premiere of British composer Arthur Butterworth's Suite for viola and cello, Opus 13. The Melos Ensemble performed regularly in Europe and toured the United States for the first of many times in 1966. Melos released some 50 commercial recordings and presented its 25th anniversary concert in London in 1975. Weil was active as an instructor and was particularly involved in efforts to encourage new chamber players. As a result, several different educational institutions have offered scholarships and prizes in his name. He performed with the English Chamber Orchestra.