http://www.theregister.co.uk/2011/04/13/bbc_plt/

Recent experiments carried out by the BBC demonstrate how power-line
networking can interfere with FM radio and knock out DAB entirely, but
only for those who get a decent data rate.

The new study was commissioned by the BBC and authored by one current
and one former BBC engineer. The study examines transmissions coming off
PLT kit, but while they were measuring the signal strengths and
monitoring the frequencies, the engineers turned on a portable radio to
discover if it still worked. They found that it did not. That is a
critical issue as the only technical requirement for PLT kit states that
it must not prevent other devices "operat[ing] as intended". PLT kit is
required to conform to the Electromagnetic Compatibility Regulations
2006, which state that such interference can't be allowed.