Squatting, the appropriation of private or public land or property for one's own use without title or right, occurs in rural and urban areas, and in developed and developing countries. Squatting may take the form of open or furtive mass movements or of individual operations. It is the illicit consequence of the struggle for shelter, the trespass of desperation; sometimes it is denounced, sometimes disesteemed; often it is tolerated for want of a practical alternative. Uncontrolled, it harbours a formidable threat to the structure of private rights established through the centuries. The buildings are often substandard, they lack electricity, sanitation, water and access roads. They are dangerous to the inhabitants, embarrassing to governments and debilitating to society.
Rural migration to the cities for jobs, where absence of jobs or housing facilities exists, causes massive squatting in Asia, particularly in India, and in Africa and Latin America. The 1981-1982 recession produced considerable numbers of squatters in the USA. Squatting in Europe is significant in cities, although small relative to the other continents. In the UK the number of homeless has doubled in the past decade; in 1991 there was an estimated 50,000 squatters nationally, rising to 60,000 in 1993.