Paul Blay <ask_me_or_get_spam_trapped@saotome.demon.co.uk> dixit:
>Aha.  Over here in good old イギリス (however you define it)
>I think there's some rule that if your boundary has been at a certain 
>point for a long enough period of time unchallenged whoever might be 
>said to own that land on paper doesn't get to get it back.*

Here it's called "adverse possession". You have to have been squatting
unchallenged for at least 15 years, after which the owner can't sue to 
get it back. It's a bit more complicated to get title to the land.

It's no longer part of Common Law here, as it's covered by special 
legislation which encodes what was previously Common Law.

-- 
Jim Breen        http://www.csse.monash.edu.au/~jwb/
Clayton School of Information Technology,
Monash University, VIC 3800, Australia 
ジム・ブリーン@モナシュ大学