This thesis is a study of British music for clarinet and piano composed between the years 1880 and 1945. The research has established a considerable repertoire of pieces, many of which are completely unknown to clarinettists today. There are two types, sonatas and character pieces. The discussion focuses on a number of substantial works. The sonatas by William Henry Hadow, William Henry Bell, George Frederick Linstead and Roger Fiske have been published (2000) in connection with this study, and critical analyses of the sonatas by Hadow and Fiske are included in the thesis, as are analyses of 'character' pieces by Richard Henry Walthew and Joseph Charles Holbrooke. It is the author's opinion that many of the works discovered demand close attention from contemporary performers. The thesis includes chapters on the British social background and its effect on musical activity; on Brahms's influence; on instruments and on the British playing tradition. The Brahms/Mohifeld relationship was probably the single most important element in establishing a strong clarinet culture in Britain at the turn of the 20th century. Native compositions were extremely popular throughout the period and indigenous performers achieved high levels of technical and artistic ability. The research noted a gradual swing away from the 'simple-system' towards the 'Boehm-system'. However, neither system dominated the other and throughout the period many disparate instrumental systems were in use in the British Isles. A chapter on performance practice draws upon evidence from early recordings. Playing before 1900 was regimented and exact in execution. After the turn of the 20th century there was a move towards freer, less restricted playing. This culminated in the outstanding playing of Reginald Kell. His refinement and artistry were unsurpassed by any other native performer of the period.