made famous (well, known out side of UK) by the book (and play, and movie) The Borstal Boy, by Brendan Behan.

it taught me the word triangle (for a prison gaurd)--from the key rings they carried..)

but its hard to have a discussion about brendan behan--he was arrested with an alarm clock in his luggage--proof positive he was building a bomb--(since there can be no other reason a irish man in the UK would in possesion of an alarm clock. )