Radio played an important but undervalued role in the development of 20th century drama. The BBC was first in the field in 1924 and, with the technological advance of Dramatic Control Panel, quickly created a wholly radiogenic form far more experimental than contemporary theatre or film. The age of experiment was over by 1930 and, though the secondary forms of dramatisation and adaptation came into their own, the single radio play became increasingly theatrical and ultimately unsatisfactory in a sound-only medium. The 1950s, however, saw the rebirth of the radiogenic radio play, not only on the minority Third Programme but across all channels, with radio for the first time nurturing the talents that would go on to achieve eminence in theatre and television. The resultant paradigm of high dramatic art combined with straightforward narrative entertainment, produced in bulk, enabled BBC radio drama to resist the challenge of television and continues, broadly, to the present day.
From the abstract to my doctoral thesis, Radio Drama at the Crossroads, De Montfort University 2008