Under the Occupiers Liability Act 1957, all lawful visitors to an occupierís land are protected. The occupier has an obligation under the act to take reasonable care for the safety of the lawful visitor and therefore in the event of an accident claim which has resulted from a lack of care by the occupier, the claim should succeed. This applies only if the visitor is on the premises lawfully. Examples would be shoppers in a supermarket, a postman delivering letters to your house, and even employees working at their place of employment, although they are also protected by other legislation and regulations. Accident claims which result from someone trespassing on an occupierís land has less chance of success than a claim resulting from an incident involving a lawful visitor. The reason for this is that the law recognises the right of people to be protected when visiting othersí premises at the invitation or with the permission of the occupier, but when there is no invitation or permission the law is reluctant to protect the visitor.
For many years accident claims resulting from an injury to a trespasser would have failed. The courts eventually recognised that even trespassers have rights, and imposed a "duty of common humanity" on an occupier to warn trespassers of any dangers on their land which may not be immediately obvious but which may be known to the occupier. This duty applies to trespassers who are known to be on the land or who could be anticipated by the occupier (such as children climbing through a broken fence to play on a railway line). The duty to children is naturally higher than to adults as children are less able to anticipate dangers than adults would be. In recent years accident claims from trespassers have been less successful as the courts have sought to further restrict trespassersí rights by drawing a distinction between the nature of a hazard and the activity of the trespasser when deciding on liability. For instance, if it is the trespasserís activity on the land which causes the accident and not the state of the occupierís premises, then the claim would fail. Accident claims resulting from trespass are inherently difficult and whilst trespassers have rights, they are intentionally restricted by the courts.