Contributory negligence does not refer to the breach of a duty of care. Rather, it refers to a careless act or omission of the plaintiff which contributes to the loss or damage which forms the subject of the plaintiff’s claim for damages. At common law, the contributory negligence of the plaintiff is not a defence to a claim for breach of contract. In other words, unless the contract provides to the contrary, it is not a defence to a claim for breach of contract if a defendant to show the plaintiff’s carelessness contributed to the loss or damage which forms the subject of the plaintiffs claim.
Nevertheless, the requirement that the plaintiff prove that its loss or damage was caused by the defendants breach of contract necessarily means that if the plaintiff’s own carelessness breaks the chain of causation between a breach in the loss or damage the plaintiff will fail, not on the basis of contributory negligence but on the basis that the loss or damage was not caused by the breach. The positioning port was somewhat different. At least in relation to the tort of negligence, at common law plaintiff would fail completely in relation to any claim relying on loss or damage resulting in part from the plaintiff’s own carelessness. This defence of contributory negligence operated in addition to the causation requirement. However, the law is modified by the apportionment legislation, under which contributory negligence ceased to be a total defence. In place of the all nothing approach of the common law, the apportionment legislation requires the court to reduce the plaintiff’s claim to reflect the plaintiff’s degree responsibility for loss or damage.
Under a series of High Court decisions there was considerable doubt whether the legislation, as originally enacted, applied the cleansing contract. The High Court has held a number of occasions that the legislation does not apply to cleansing contract. The effect of that decision was soon reversed by legislation amending the apportionment legislation in most jurisdictions. However the key case which the High Court used to expound this principle continues to govern the matter in Western Australia and also in situations to which the amended legislation does not apply.
