The BBC Third Programme was a national radio service produced and broadcast by the BBC between 1946 and 1970. It first went on the air on 29 September 1946 and quickly became one of the leading cultural and intellectual forces in Britain, playing a crucial role in disseminating the arts. It was the BBC's third national radio network, the other two being the Home Service (mainly speech-based) and the Light Programme, principally devoted to light entertainment and music. The Third Programme, as a distinct service, was finally subsumed into BBC Radio 3 on 4 April 1970.