Court case[1912] 1 KB 496

A fire broke out on the plaintiff's heath land. The defendant was the head gamekeeper of a person who held the shooting rights over the adjoining land, on which pheasants were nesting. To prevent the fire from spreading to that land, the defendant set fire to strips of heather on the plaintiff's land between the fire and his master's land, creating a fire break. In the event the main fire was put out by other people and never reached the fire break. The plaintiff sued the defendant for trespass to his land.

The Court of Appeal held that the defendant was not liable. There was a real and imminent danger to his master's property; the defendant acted to protect it, and the steps he took were reasonable in the circumstances as they appeared at the time. It was immaterial that, in the result, the fire was extinguished by others and the defendant's act proved unnecessary: the defence of necessity is judged by whether a reasonable man would have thought the danger real and imminent and the measures reasonable, not with the benefit of hindsight.