Bolton v. Stone
Bolton v. Stone [1951] A.C. 850, [1951] 1 All E.R. 1078 (H.L.) is the leading House of Lords case on tort law that estalishes the doctrine of the standard of care.
During a game of cricket the ball was hit out of the park hitting the plaintiff who was standing on a nearby highway at a distance of about 100 yards from the batter. Over the whole history of the cricket park a ball had been hit that far only about six times in 30 years.
The House of Lords found that there was no negligence. They calculated whether the defendant had a duty to the plaintiff by taking into account the foressability of the risk was and the cost of measures to prevent the risk. From there they estimated what precautions would be taken by a reasonable person in the position of the defendant. Since the event was so highly improbable there was no way a reasonable person could have anticipated the harm to the plaintiff.