Other than the pirate stations around London, they're not quite as proliferate as they once were with the advent of the internet. They have a colourful history in the UK however, with some stations broadcasting from international waters in the 60's just off the UK to circumvent the monopoly the BBC and record companies had on music. I highly recommend watching 'The Boat That Rocked' for a good comedy based on it.

Below are some interesting reads on the culture:

https://en.wikipedia.org/wiki/Pirate_radio_in_the_United_Kin...

https://www.transdiffusion.org/2008/08/01/on_the_run_the

http://www.thepiratearchive.net/

https://web.archive.org/web/20090324075718/http://www.freewe...