Heard all around London, even in polite conversation: loo.
As in, the W.C., the toilet, the restroom, the john, the head, the necessary, etc.
Most amusingly, loo appears to be the best word to ask an etymologist about if you want to really piss him off, for there are many fanciful and amusing theories about the derivation of the word, but no one knows for sure whence it sprang.
(word of the day/phrase of the day: I highlight a word or phrase, especially new coinages or clever usages, that tickles me)
Loos often attract bugs, though, don't they? :->
Thanks for pointing out my error -- I've corrected it. I knew the correct word, actually: put my error down to trying to post early in the morning while jet-lagged after having been out pubbing the night before.