Any person present on or in occupation or possession of land without permission is a trespasser, whether they were originally there under a lease which has expired or have outstayed some other form of permission or licence to be there or whether they were never given any form of permission.
Squatters – who take up occupation of land as a dwelling – have the benefit of the Protection from Eviction Act 1977 under which they can only be evicted under a court order in proceedings following a specific statutory form of notice to quit.
Travellers, whether Romany, Irish or “New Age”, can be in a stronger position against local authorities seeking to evict them because the latter have statutory duties to provide sites and consider homelessness. These factors do not apply to private landowners but nevertheless no one who is occupying land residentially can be evicted without due process attempting to do so or harassing them (for example by turning off water or energy supplies) will be a criminal offence.
Great care should be taken to avoid a trespasser remaining in possession of land for 10 years (12 years if unregistered land) without permission because by doing so they can acquire a right to be registered as the owner and the rightful or “paper title” owner can lose all rights to it.