Volenti non fit iniuria (or injuria) (Latin: "to a willing person, injury is not done") is a common law doctrine which states that if someone willingly places themselves in a position where harm might result, knowing that some degree of harm might result, they are not able to bring a claim against the other party in tort or delict. Volenti applies only to the risk which a reasonable person would consider them as having assumed by their actions; thus a boxer consents to being hit, and to the injuries that might be expected from being hit, but does not consent to (for example) his opponent striking him with an iron bar, or punching him outside the usual terms of boxing. Volenti is also known as a "voluntary assumption of risk". Volenti is sometimes described as the plaintiff "consenting to run a risk". In this context, volenti can be distinguished from legal consent in that the latter can prevent some torts arising in the first place. For example, consent to a medical procedure prevents the procedure from being a trespass to the person, or consenting to a person visiting one's land prevents them from being a trespasser. History Volenti non fit injuria is an often-quoted form of the legal maxim formulated by the Roman jurist Ulpian which reads in original: Nulla iniuria est, quæ in volentem fiat. English law In English tort law, volenti is a full defence, i.e. it fully exonerates the defendant who succeeds in proving it. The defence has two main elements: The claimant was fully aware of all the risks involved, including both the nature and the extent of the risk; and The claimant expressly (by statement) or implicitly (by actions) consented to waive all claims for damages. Knowledge of the risk is not sufficient: sciens non est volens ("knowing is not volunteering"). Consent must be free and voluntary, i.e. not brought about by duress. If the relationship between the claimant and defendant is such that there is doubt as to whether the consent was truly voluntary, such as the relationship between workers and employers, the courts are unlikely to find volenti. It is not easy for a defendant to show both elements and therefore comparative negligence usually constitutes a better defence in many cases. Note however that comparative negligence is a partial defence, i.e. it usually leads to a reduction of payable damages rather than a