Criminal trespass is illegally entering into or remaining in a building or structure. This is distinguished from burglary by the fact that no other crime is intended.
In countries like the UK in which most land is somebody's property, following the enclosure of common land, trespass has been recognized as a dispute between individuals rather than a crime against society, although breaking and entry is a crime. Because of the lack of provision for those without a place to live, the existence of a grey area in relation to trespass has been essential to the provision of a legal "stopping place" where the underprivileged could stake a temporary claim.
In the UK in 1994 it was estimated that over 100,000 people were likely to be living semi-legally on somebody else's property. These include gypsies and squatters.