All of the BBC's domestic output , both radio and TV, is funded primarily through the television licence fee (although, of course, the BBC also has a commercial division- selling DVDs, books, etc - which also contributes to the Corporation's funds).
Roughly 17% of your TV licence fee goes towards funding the BBC's radio services. These include Radio 1, Radio 2, Radio 3, Radio 4, Five Live, Radio Scotland, Radio Wales, 6 Music, BBC7 and about 50 local or regional radio stations.
http://www.bbc.co.uk/info/licencefee/
Chris