Last night's concert at the Library of Congress offered a welcome opportunity to hear the Alberni String Quartet from England. Looking the very image of four dignified country gentlemen -- the bearded second violinist even bears a faint resemblance to Prince Albert -- the ensemble reflected some of the finest qualities of the British musical tradition.

Formed in 1960 at London's Royal Academy of Music, the quartet has worked with several of Britain's major composers, particularly Benjamin Britten. He even coached them on his Quartet No. 1 in D major, which, not surprisingly, formed the expressive heart of the evening's program. Written when Britten was still in his twenties and not yet the great vocal composer, the Quartet contains both the touching intensity and the engaging impudence of youth. It is, incidentally, dedicated to the library's great music patron, Elizabeth Sprague Coolidge, and had not been heard in the Coolidge Auditorium since its first performance there in 1941.

For the members of the Alberni, the music seems to be second nature. With sure insight they captured the atmospheric opening mood, the pointed whimsy of the second movement, the sustained song of the slow third movement and the graceful cheekiness of the last. Beethoven's F-Major Quartet, Op. 59, No. 1, also benefited from the group's strong sense of unity and proportion. Least successful was the opening Haydn Quartet, marred by too thick an ensemble sound and frequent intonation problems from the first violinist.