With the advancement of TV, radio drama began to die out, although there are still pockets of production. And in Great Britain, it actually still thrives, especially with shows like 'The Archers'. And a multiverse great - 'The Hitch-Hiker's Guide To The Galaxy' - began life in the radio dimension.
Right now, I'm listening to BBC's Radio 4 and its podcast of a new episode of 'Torchwood' which is tied into the big scientific news of the day - the activation of the CERN super collider in Switzerland.
Captain Jack, Gwen, and Ianto were called to the event by Dr. Martha Jones to investigate a series of disappearances. Basically, even though these are the Torchwood characters we know from Toobworld, they are separate from their counterparts. Still, they mirror the televersions pretty much exactly - several times Owen and Tosh are mentioned and as being dead, so we know it takes place after the second season finale. But since there is no mention of the events in the fourth season finale for 'Doctor Who', we know that Davros' plan to steal the Earth has not taken place yet.
I'm sixteen plus minutes into the radio play and the symptoms of the victim they're examining resemble those of Agent John Scott in last night's premiere of 'Fringe': the body is becoming translucent.
I'm still listening to the show, so I can't give it away even if I wanted to. But if you wanted to hear it for yourself, it's now available on podcast. Just follow this BBC4 radio link. (However, it's only available for download the next seven days.)