A defence available where it is proved that the claimant's own negligence contributed to its loss or damage. The Law Reform (Contributory Negligence) Act 1945 provides for apportionment of loss where the fault of both claimant and defendant have contributed to the damage. "Fault" is defined in the Act as "negligence or other act or omission which gives rise to liability in tort or would, apart from this Act, give rise to the defence of contributory negligence" (section 4). A claim for damages will be reduced to such extent as the court thinks just and equitable having regard to the claimant's share in responsibility for the damage. The Act was designed for the tort of negligence but can be applied to cases of contractual breaches where the defendant's liability in contract is the same as its liability in negligence.

For more information, see Practice note, Contributory negligence and contribution.