They're mainly North Korean defectors living in Seoul, who run a radio station broadcasting news into North Korea for an hour a day.

NPR: N. Korean Defectors Fight Regime with the Radio

Ofcom says that there are other avenues open for legal broadcasting, such as setting up a community radio station.

BBC: Pirate radio 'puts lives at risk'

The radio broadcaster of the year award went to former Radio 4 newsreader Charlotte Green, who retired from broadcasting in January after 25 years on the station.

BBC: Parade's End wins four Broadcasting Press Guild awards