"mike" wrote in message
...

But hasn't it already been paid for by the broadcaster?

The broadcaster has paid for the right to transmit the music over the radio.
Their licence fee is calculated upon the expected number of people who will
listen to that transmission. Playing the transmission to others, execpt for
strictly private purposes, is a separate performance of the work, which
increases the number of people listening, and needs its own licence.

Colin Bignell