A right to housing
A neat little snippet from the latest issue of Green World, the Green Party magazine.
"In Wales, landless peasants would work round the clock to complete the shell of a "tai unnos", or one-night house, as a right of tenure would be gained if smoke was seen rising from the chimney before sunrise on the following day. The shell could then be finished off and added to as time and resources allowed."
Here's the BBC's version (which seems rather more doubtful about the legal position), and a bit on the archaeology of a settlement apparently so constituted.