chapter  4
Unreasonableness/Abnormality
Pages 18

In Reeves v Commissioner of Police of the Metropolis1 Lord Hobhouse observed that ‘[r]easonable human responses to situations [created by the defendant’s negligence] are not treated as causative; they are a normal consequence of the antecedent event and it is that event which is described as the cause.’2 The operation of an intervening agency will not ordinarily relieve the defendant from liability if it is considered by the court to be a not abnormal incident of the risk created by the defendant or if the response of the plaintiff or third person to the situation created by the defendant’s negligence is considered not unreasonable in the circumstances.3 Generally speaking, the more unreasonable the conduct of the intervening human agent or the more abnormal the intervening event, the more prone a court will be to uphold a defendant’s novus actus plea.4 Courts have assessed how normal or reasonable the reaction of the plaintiff or a third party has been to the situation in which the defendant’s negligence has placed them. This assessment is typically made in cases involving imminent fear of injury to oneself or the desire to avoid significant inconvenience.