In 1998 the Health and Safety in Employment Act 1992 was amended in order to more clearly state the responsibilities of persons in control of a place of work in regard to persons present in that place of work for recreation, or to other authorised visitors.  This has particular relevance to farmers where that farmland is often a site of recreational activity.

Under the new Section 16 of the Act farmers have a duty to warn authorised visitors of work-related, out-of-the-ordinary hazards.
An authorised visitor is one who comes on to their farm WITH THEIR EXPRESS PERMISSION.  It includes people who come for leisure or recreational activities such as hunting, shooting, orienteering, fishing, picnicking, rock climbing, swimming, mushroom gathering, horse riding, trail bike riding, hang gliding and so on.

A work-related out-of-the-ordinary hazard is a HAZARD that:

Arises from some work activity on the farm;

and

Wouldn’t normally be expected by a visitor;

and

Could cause a person serious harm.

Examples include: trees being felled, blasting, earthmoving machinery operating, or where pest control operators are working.

NATURAL HAZARDS ARE EXCLUDED.  Farmers are not required to warn visitors of natural hazards on their farm, such as bluffs, caves, landslides, swamps, wasp nest and so on.

Farmers need only give a VERBAL WARNING about the HAZARD.  This needs to be done AT THE TIME that EXPRESS PERMISSION is sought to enter the farmland in question.  If a group of people are involved (such as an orienteering club), it’s sufficient to give warning to a representative of the group.  However this does not exempt the farmer from taking action to deal with any inherently dangerous situation on their property.

The warning can be given by a farm manager if he or she is the person giving permission.