1832 .
But seriously: In the early years of the 20th century. By the mid 1920s it was well established.
The BBC School Radio, which is the audio division of BBC Schools, began broadcasting April, 4th 1924. At this time it was still referred to as a company. In 1927 it became a corporation.
BBC Radio Kent, the BBC local radio for the English county of Kent, began broadcasting on 18 December 1970. The frequencies are 96.7, 97.6, 104.2, 774 and 1602.
On Saturday the 30th of September 1967. The first DJ (Tony Blackburn) opened his show with the song "Flowers in the Rain" by 'The Move'.
BBC Radio Kent was created on 1970-12-18.
BBC Radio Foyle was created on 1979-09-11.
BBC Radio Sessions was created in 2007.
BBC Radio York was created on 1983-07-04.
BBC Radio Ulster was created on 1975-01-01.
BBC Radio Norfolk was created on 1980-09-11.
BBC Radio Foyle was created on 1979-09-11.
BBC Radio Durham was created in 1968.
BBC Radio Sessions was created in 2007.
BBC Radio Orkney was created in 1977-05.
BBC Radio Bristol was created in 1970-09.
BBC Radio Shetland was created in 1977-05.
BBC Radio Sheffield was created on 1967-11-15.
BBC Radio Lancashire was created on 1971-01-26.
BBC Radio Leeds was created on 1968-06-24.
BBC Radio Gloucestershire was created on 1988-10-03.
BBC Radio Cumbria was created on 1973-11-24.
BBC Radio nan Gàidheal was created in 1985.